Which of the following is an open statement? Question 7 options: ∠ABC is obtuse. An angle with measure 105° is obtuse. An angle with measure 82° is obtuse. An angle with measure 40° is acute.

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.