JSFiddle - React, Tailwind, and code Playground

HTML

<select class="form-control" data-val="true" data-val-number="The field OriginatingInstitutionId must be a number." id="OriginatingInstitutionId" name="OriginatingInstitutionId"><option value="">Select source institution...</option>
<option value="3">Alaska Native Medical Center, Anchorage, AK</option>
<option value="4">Baptist Medical Center, Jacksonville, FL</option>
<option value="5">Baptist Medical Center, San Antonio, FL</option>
<option value="10">Northstar Hospital, Nome, AK</option>
<option value="14">Melwood, Pittsburgh, PA</option>
<option value="15">San Leandro Hospital, San Leandro, CA</option>
<option value="17">ST Regis Hospital, Philidelphia, Pa</option>
<option selected="selected" value="2">The Shire (inactive)</option>
</select>

JavaScript

alert($("#OriginatingInstitutionId").children('option').length);