title: Display checkboxes values from ACF (Wordpress) on front
body: <p>I'm having some trouble trying to display checkboxes values created with ACF.
  I have a group of 12 checkboxes made with ACF, where each checkbox is a month:
  jan : Jan / feb : Feb / mar : Mar / etc.</p>
  
  <p>What i need to achieve is to display all of those 12 values in the frontend, with a particular CSS class if the month has been checked in the backend. For example, if the user checks "Jan", "Apr", "Jul" and "Sep":</p>
  
  <pre><code>&lt;span class="selected"&gt;Jan&lt;/span&gt;
  &lt;span&gt;Feb&lt;/span&gt;
  &lt;span&gt;Mar&lt;/span&gt;
  &lt;span class="selected"&gt;Apr&lt;/span&gt;
  &lt;span&gt;May&lt;/span&gt;
  &lt;span&gt;Jun&lt;/span&gt;
  &lt;span class="selected"&gt;Jul&lt;/span&gt;
  &lt;span&gt;Ago&lt;/span&gt;
  &lt;span class="selected"&gt;Sep&lt;/span&gt;
  &lt;span&gt;Oct&lt;/span&gt;
  &lt;span&gt;Nov&lt;/span&gt;
  &lt;span&gt;Dec&lt;/span&gt;
  </code></pre>
  
  <p>Using the example code from the docs  (<a href="https://www.advancedcustomfields.com/resources/checkbox/" rel="nofollow noreferrer">https://www.advancedcustomfields.com/resources/checkbox/</a>), I'm only getting the selected months but not all months in the frontend:</p>
  
  <pre><code>&lt;span&gt;Jan&lt;/span&gt;
  &lt;span&gt;Apr&lt;/span&gt;
  &lt;span&gt;Jul&lt;/span&gt;
  &lt;span&gt;Sep&lt;/span&gt;
  </code></pre>