Aforest is in the shape of a rectangle 5 miles long and 3 miles wide. the density of the trees at a distance of x miles form the 5 mile side is given by p(x) trees per square mile. which expression gives the number of trees in the forest?

a. integral from 0-3 p(x) dx
b.3 integral from 0-3 p(x) dx
c.5 integral from 0-3 p(x) dx
d. 3 integral from 0-3 p'(x) dx
e.5 integral from 0-3 p'(x) dx