title: How to get field options array from WooCommerce checkout billing country?
body: <p>In woocommerce I am using the following code to customize the checkout billing fields using the filter hook <code>woocommerce_checkout_fields</code> :</p>
  
  <p><a href="https://i.stack.imgur.com/kFUOX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kFUOX.png" alt="enter image description here"></a></p>
  
  <p>I don't know how to get the array of billing countries key / value pairs for the 'options' key.</p>
  
  <p>How can get in WooCommerce checkout the billing country field options array?</p>