<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container">
<div class="row">
<div class="col-sm-3">
<a href="#" class="btn btn-lg red">
<span class="fa fa-home"></span>button
</a>
</div>
<div class="col-sm-3">
<a href="#" class="btn btn-sm red">
<span class="fa fa-home"></span>button
</a>
</div>
<div class="col-sm-3">
<a href="#" class="btn btn-xs red">
<span class="fa fa-home"></span>button
</a>
</div>
</div>
</div>