Grid System for Posts

I have searched everywhere for an answer to this but have had no luck… I have a grid displaying post thumbnail images. The grid is currently set to display 6 boxes per row. All good to that point.

Now there is an additional line of code specifying that column 6 has a unique/additional class than the others.

<?php echo (($c != $bpr) ? ” : ‘reverse’); ?>”>

What I want is for column 5 and 6 to have a the unique class which I’ve called “reverse.” I cannot figure out how to edit that bit of code. Here is my entire code:

<ul>

            <?php
                query_posts( 'cat=4' ); //let’s get the data from Category Id of 4, which in our case is Team.
                $c = 1; //counter
                $bpr = 6; //number of column in each row

                if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

                        <?php if ( has_post_thumbnail()) { ?>

                <li class="thumbnail <?php echo (($c != $bpr) ? '' : 'reverse'); ?>">

				<a href="<?php the_permalink() ?>" title="<?php printf(__('%s','rys'), get_the_title()) ?>" rel="bookmark" class="image"><?php the_post_thumbnail('grid-thumb'); ?></a>

				<div class="info-box" style="display:none;">
					<div class="executive-image" style="overflow:hidden;" class="image">
					<a href="<?php the_permalink() ?>" title="<?php printf(__('%s','rys'), get_the_title()) ?>" rel="bookmark"><?php the_post_thumbnail('grid-thumb'); ?></a>
					</div>

					<div class="info">
						<p class="name"><?php the_title(); ?></p>
						<p><?php the_field('designation'); ?></p>
					</div>
				</div><!-- end .info-box -->

                            </li>

                        <?php } else { ?>
                            <img src="<?php bloginfo('template_directory'); ?>/images/no-thumbnail.jpg" alt="No Thumbnail" />
                        <?php } ?>

            <?php
            if($c == $bpr) { //we add a condition here to see if counter is equal to the number of column.
                echo '<div class="clear"></div>';
                $c = 0; // back the counter to 0 if the condition above is true.
            }
            $c++; // increment counter of 1 until it hits the limit of column of every row.

            endwhile;
            else: // display if category is empty.
            ?>
                <h2><?php _e( 'Oops!', 'rys' ); ?></h2>
                <p><?php _e( 'Sorry, seems there are no post at the moment.', 'rys' ); ?></p>
            <?php
            endif;
            wp_reset_query();
            ?>

	</ul>