A researcher randomly selected 158 personal vehicles and noted the type of vehicle and its color. The two-way table displays the data. Suppose a vehicle is randomly selected. Let event C = convertible and R = red. What is the value of P(R|C)?

A). 29/158

B). 43/158

C). 20/43

D). 20/29

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.