The sine regression model uses a form that approximates the data as an algebraic representation of the graph. Choose the sine regression model from the following:
ay=sin(x +c)+d
b. y=mx+
C. y - Ar? +BX+C
d.
-6+ 6²-4ac
2a

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.