<p><?php the_field("status"); ?> </p>

<?php
   //store the value in a variable first
   $option = get_field("status");
    if($option=="K dispozicii"){
     ?> <p style="color:green">$option</p> <?php
        }elseif ($option=="Obsazeno") {
           ?> <p style="color:red">$option</p> <?php
        }
    ?>