JSFiddle - React, Tailwind, and code Playground
HTML
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
<select id="sel">
<option value="">...</option>
<option value="1" data-toggle="modal" data-target="#myModal" data-whatever="1">Valor 1</option>
<option value="2" data-toggle="modal" data-target="#myModal" data-whatever="2">Valor 2</option>
</select>
<br>
<br>
<br>
<!-- Trigger the modal with a button -->
<button type="button" data-toggle="modal" data-target="#myModal" data-whatever="btn">Open Modal</button>
<br>
<br>
<!-- Modal -->
<div id="myModal" class="modal fade" role="dialog">
<div class="modal-dialog">
<!-- Modal content-->
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal">×</button>
<h4 class="modal-title">Modal Header</h4>
</div>
<div class="modal-body">
<p>Some text in the modal.</p>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
</div>
</div>
</div>
</div>
JavaScript
$(document).ready(function(){
$('#myModal').on('show.bs.modal', function (e) {
// Quando vem do botão eu pego o data-whatever
var target = $(e.relatedTarget).data("whatever");
if (target == "btn"){
$(this).find(".modal-body").html("veio do botao");
}else{
if ((target == "1") || (target == "2")){
$(this).find(".modal-body").html(target);
$(this).find(".modal-body").html("veio do select");
}else{
$(this).find(".modal-body").html("indefinido");
}
}
});
});