How to convert select to HTML with PHP tags inside of it [closed]

An example: your code

<option value="0" '
    .selected($horizon_featured,'normal',false)
    .'>Descending</option>

HTML code with some PHP mixed in:

<option value="0" <?php echo .selected($horizon_featured,'normal',false); ?>>Descending</option>

Basically, you just put a <?php echo $something;?> where you want the PHP stuff to be.