JSFiddle - React, Tailwind, and code Playground

HTML

<div>
	<select class="dk_multioptions_inner" tabindex="5" id="multiple" style="width: auto; visibility: visible; position: relative; font-weight:bold;" multiple="multiple">
		<option style="width: 150px;" value="Diploma degree">Diploma degree</option>
		<option value="Technical degree">Technical degree</option>
		<option  value="bachelor degree">Bachelor degree</option>
		<option value="Masters degree">Masters degree</option>
		<option value="Masters degree in technology">Masters degree in technology</option>
	</select>
</div>

CSS

.dk_multioptions_inner
{
  margin-left:-1px;
  margin-top:2px;
  color: #000000;
  max-height: 250px;
  border:1px solid #c997ba;
  background-color: #eeeeed;
  background-image: -moz-linear-gradient(top, #f9f9f8, #dadad9);
  background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#f9f9f8), to(#dadad9));
  background-image: -webkit-linear-gradient(top, #f9f9f8, #dadad9);
  background-image: -o-linear-gradient(top, #f9f9f8, #dadad9);
  background-image: linear-gradient(to bottom, #f9f9f8, #dadad9);
  border-radius: 4px;
  -webkit-border-top-right-radius:0px;border-top-right-radius:0px;-moz-border-radius-topright:0px;
  -webkit-border-top-left-radius:0px;border-top-left-radius:0px;-moz-border-radius-topleft:0px;
    font-weight: bold;
    cursor: pointer;
    font-size: 14px;
  }

JavaScript

$('.dk_multioptions_inner').find('option').css("height", "30px");