Получить массив экзамена, используя preg_match_all и foreach

Мне нужен массив для экзамена, но результат после использования regex и foreach не тот, что я хочу.

Мой текущий результат:

Array
(
    [0] => Array
        (
            [0] => 1 Q 1.Question 1? A 0 - Answer 11
            [1] => 1 Q 1.Question 1? A 1 - Answer 12
            [2] => 1 Q 1.Question 1? A 2 - Answer 13
            [3] => 1 Q 1.Question 1? A 3 - Answer 21
            [4] => 1 Q 1.Question 1? A 4 - Answer 22
            [5] => 1 Q 1.Question 1? A 5 -  Answer 31
            [6] => 1 Q 1.Question 1? A 6 -  Answer 32
            [7] => 1 Q 1.Question 1? A 7 -  Answer 33
            [8] => 2 Q 2.Question 2? A 0 - Answer 11
            [9] => 2 Q 2.Question 2? A 1 - Answer 12
            [10] => 2 Q 2.Question 2? A 2 - Answer 13
            [11] => 2 Q 2.Question 2? A 3 - Answer 21
            [12] => 2 Q 2.Question 2? A 4 - Answer 22
            [13] => 2 Q 2.Question 2? A 5 -  Answer 31
            [14] => 2 Q 2.Question 2? A 6 -  Answer 32
            [15] => 2 Q 2.Question 2? A 7 -  Answer 33
            [16] => 3 Q 3. Question 3? A 0 - Answer 11
            [17] => 3 Q 3. Question 3? A 1 - Answer 12
            [18] => 3 Q 3. Question 3? A 2 - Answer 13
            [19] => 3 Q 3. Question 3? A 3 - Answer 21
            [20] => 3 Q 3. Question 3? A 4 - Answer 22
            [21] => 3 Q 3. Question 3? A 5 -  Answer 31
            [22] => 3 Q 3. Question 3? A 6 -  Answer 32
            [23] => 3 Q 3. Question 3? A 7 -  Answer 33
        )

)

В приведенном выше результате указано, сколько раз вопрос и ответ повторяются несколько раз.

Мой желаемый результат:

Array
(
    [0] => Array
        (
            [0] => 1 Q 1.Question 1? A 0 - Answer 11
            [1] => 1 Q 1.Question 1? A 1 - Answer 12
            [2] => 1 Q 1.Question 1? A 2 - Answer 13
)
[1] => Array
        (
            [3] => 2 Q 2.Question 2? A 0 - Answer 21
            [4] => 2 Q 2.Question 2? A 1 - Answer 22
)
[2] => Array
        (
            [5] => 3 Q 3.Question 3? A 0 -  Answer 31
            [6] => 3 Q 3.Question 3? A 1 -  Answer 32
            [7] => 3 Q 3.Question 3? A 2 -  Answer 33
         )

)

Мой текущий код (работает онлайн):

<?php
$re_question = "'<b>(.*?)</b>'si";
$re_answer = '#<input[^>]* value = "([a-z]\.\)(.*?)")>#s';

$str = '<b>1.Question 1?</b><div class = "data-check" style = "padding-left:25px;"><input class = "data-form-input" type = "radio" name = "q11111" value = "a.)Answer 11">a.)Answer 11</div><div class = "data-check" style = "padding-left:25px;"><input class = "data-form-input" type = "radio" name = "q11111" value = "b.)Answer 12">b.)Answer 12</div><div class = "data-check" style = "padding-left:25px;"><input class = "data-form-input" type = "radio" name = "q11111" value = "b.)Answer 13">b.)Answer 13</div><br><b>2.Question 2?</b><div class = "data-check" style = "padding-left:25px;"><input class = "data-form-input" type = "radio" name = "q11111" value = "a.)Answer 21">a.)Answer 21</div><div class = "data-check" style = "padding-left:25px;"><input class = "data-form-input" type = "radio" name = "q22" value = "b.)Answer 22">b.)Answer22</div><br><b>3. Question 3?</b><div class = "data-check" style = "padding-left: 25px;"> <input class = "data-form-input" type = "radio" name = "q33333" value = "a.) Answer 31"> a.) Answer 31 </div><div class = "data-check" style = "padding-left: 25px;"> <input class = "data-form-input" type = "radio" name = "q33333" value = "b.) Answer 32"> b.) Answer 32 </div> </div><div class = "data-check" style = "padding-left: 25px;"> <input class = "data-form-input" type = "radio" name = "q33333" value = "b.) Answer 33"> b.) Answer 33 </div>';

$questions = "";
$answers = [];
$questions_and_answers = [];
$answer_number = 0;
$question_number = 0;
//question
preg_match_all($re_question, $str, $matches_question, PREG_SET_ORDER, 0);
//if (count($matches_question) > 0) {
foreach($matches_question as $sentence_question){
    $answer_number = 0;
    $each_question = $sentence_question[1];
    $question_number +=1;
preg_match_all($re_answer, $str, $matches_answer, PREG_SET_ORDER, 0);
foreach($matches_answer as $sentence_answer){
    $questions_and_answers[] = $question_number. ' Q ' .$each_question. ' A ' .$answer_number.' - '.$sentence_answer[2];
    $answer_number +=1;
}    
//$result = array_merge($questions);
$result = array_merge([$questions_and_answers]);
 
}

print_r($result);
?>

Не могли бы вы помочь мне, как это решить?