<!-- Latest compiled and minified CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
<!-- jQuery library -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js"></script>
<!-- Popper JS -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<!-- Latest compiled JavaScript -->
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>

<div class="container">
  <strong>Which option do you want to choose?</strong>
  <div class="form-check">
    <input class="form-check-input" type="radio" name="exampleRadios" id="exampleRadios1" value="a" checked>
    <label class="form-check-label" for="exampleRadios1">
            A
        </label>
  </div>

  <div class="form-check">
    <input class="form-check-input" type="radio" name="exampleRadios" id="exampleRadios2" value="b">
    <label class="form-check-label" for="exampleRadios2">
            B
        </label>
  </div>

  <div class="form-check">
    <input class="form-check-input" type="radio" name="exampleRadios" id="exampleRadios3" value="c">
    <label class="form-check-label" for="exampleRadios3">
            C
        </label>
  </div>
  
  <div class="form-check">
    <input class="form-check-input" type="radio" name="exampleRadios" id="exampleRadios4" value="d">
    <label class="form-check-label" for="exampleRadios4">
            D
        </label>
  </div>  
</div>

body {
  text-align: center;
  padding-top: 25px;
}