There are 5 classes with 29 students per class and 5 teachers ordering pizza. One pizza feeds 5 people. Which of the following is a good estimation of how many pizzas are needed?

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.