WP Query to dynamic options

Hi there,

I am wondering, how can I write a filter, that handles this function:

<?php $ajanlatok = new WP_Query('category_name=ajanlatok&posts_per_page=100&orderby=date&order=DESC'); ?>

<?php while ($ajanlatok->have_posts()) : $ajanlatok->the_post(); ?>
<option value="<?php the_ID(); ?>" <?php if ($_GET['offer-id'] == get_the_ID()) { echo("selected"); } ?>><?php the_title(); ?></option>
<?php endwhile; ?>