Jennifer travels from Boston , Massachusetts, to Fairfield, Connecticut, a distance of 90 miles, at a speed of 45 miles per hour, and returns at a speed of 60 miles per hour. To the nearest half mile per hour, what is Jennifer's average rate for the whole trip?
A) 50 1/2
B) 51
C) 51 1/2
D) 52 1/2
E) 53 1/2