<select class="form-control" id="resource_id" name="resource_id">
    <?php
    $parentData = Adminx_Models_Resource_Client::getResourceByParentID($this->resource_group_id);
    foreach($parentData as $key =>$val){
        ?>
        <option value="<?php echo $val['id'];?>"><?php echo $val['resource_name'];?></option>
    <?php }?>
</select>