Why my filter is not working when i am selecting any option but it is working for another control

Question

I am filtering the select box value based on the selection of the previous select box. My code is working for option 1 to option 2 but it is not working from option 2 to option 3. please look and suggest.

var allOptions = $("#option2 option");
$("#option1").change(function () {
    $("#option2 option").remove();
    $("select").prop("disabled", false);
    $(".error-message").hide();
    var classN = $("#option1 option:selected").prop("class");
    var opts = allOptions.filter("." + classN);
    $.each(opts, function (i, j) {
        $(j).appendTo("#option2");
    });
});

var allOptions2 = $("#option3 option");
$("#option2").change(function () {
    $("#option3 option").remove();
    $("select").prop("disabled", false);
    $(".error-message").hide();
    var classN2 = $("#option2 option:selected").prop("class");
    var opts2 = allOptions2.filter("." + classN2);
    $.each(opts2, function (k, l) {
        $(l).appendTo("#option3");
    });
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<select id="option1" class="mandatory form-select mb-3">
    <option value="0"></option>
    <option class="australia">Australia</option>
    <option class="austria">Austria</option>
</select>
<select id="option2" class="mandatory form-select mb-3">
    <option value="0"></option>
    <option class="australia l-a">Bachelor (honours) Degree</option>
    <option class="australia austria cyprus czech-republic denmark dubai finland germany hungary ireland malaysia japan mauritius malta singapore paris netherland poland switzerland singapore sweden spain">Bachelors</option>

    <option class="austria cyprus czech-republic denmark dubai finland germany hungary ireland malaysia japan mauritius malta singapore paris netherland poland switzerland singapore sweden spain uk usa">Masters</option>
    <option class="australia l-b">Masters (extended) degree</option>
    <option class="australia">Masters by coursework degree</option>
    <option class="australia austria canada cyprus czech-republic denmark dubai finland germany hungary ireland malaysia japan mauritius malta singapore paris netherland poland switzerland singapore sweden spain uk">PhD</option>
    <option class="australia">Vocational Education and Training (VET)</option>
</select>
<select id="option3" class="form-select mb-3">
    <option></option>
    <option class="italy">Any Qualifying</option>
    <option class="italy">PHd</option>
    <option class="australia l-b">PG</option>
    <option class="australia l-a">UG</option>
</select>