A base of a solid is bounded by x+2y=4 and coordinate axes. What is volume of solid if every cross section perpendicular to x-axis is a semicircle?

a) 2pi/3 b) 4pi?3 c) 8pi/3 d) 32pi/3 e) 64pi/3

Please help me with this calculus problem. I am so lost in my class. step by step work would be greatly appreciated. The work does not have to be completely accurate, I just need the steps. Thank you in advance.