How is this correct?

3. a family is building a circular fountain in the backyard. the yard is rectangular and measures 7x by 6x and the fountain is going to be circular with a radius of 2x. once the fountain is build, what will be the area of the remaining yard?
a. 38x^2
b. [x] 2x^2 (21 _ 2pi)
c. 42x^2 _ 2pix^2
d. 38pix^2