JSFiddle - React, Tailwind, and code Playground

HTML

<label>Select the priority level of the task:&nbsp;</label>
<select id="taskPriority" name="priority[]" multiple="multiple">
    <option value="lowImp">Low Importance</option>
    <option value="highImp">High Importance</option>
    <option value="lowUrg">Low Urgency</option>
    <option value="highUrg">High Urgency</option>
</select>
<br />
<br />

JavaScript

$(document).ready(function () {
    $('#taskPriority').on('change', function () {
        var theval = $(this).val();
        console.log(theval);
        if (jQuery.inArray('lowImp',theval) > -1) {
            $('#taskPriority').find('option[value=highImp]').prop('disabled', true);
        } 
        if (jQuery.inArray('highImp',theval) > -1) {
            $('#taskPriority').find('option[value=lowImp]').prop('disabled', true);
        }
        if (jQuery.inArray('lowUrg',theval) > -1) {
            $('#taskPriority').find('option[value=highUrg]').prop('disabled', true);
        }
        if (jQuery.inArray('highUrg',theval) > -1) {
            $('#taskPriority').find('option[value=lowUrg]').prop('disabled', true);
        }
        if(jQuery.inArray('lowImp',theval) == -1){
              $('#taskPriority').find('option[value=highImp]').prop('disabled',false);
        }
        if(jQuery.inArray('highImp',theval) == -1){
              $('#taskPriority').find('option[value=lowImp]').prop('disabled',false);
        }
        if(jQuery.inArray('lowUrg',theval) == -1){
              $('#taskPriority').find('option[value=highUrg]').prop('disabled',false);
        }
        if(jQuery.inArray('highUrg',theval) == -1){
              $('#taskPriority').find('option[value=lowUrg]').prop('disabled',false);
        }
    });
});