Block A sits on top of block B, both of which are on a table. Block A has a mass of 2.0 kg, and B has a mass of 4.0 kg. If you press downward on the top of block A with 15 N of force, what is the normal force that the table exerts up on block B?
a. 39 N
b. 44 N
c. 49 N
d. 54 N
e. 59 N
f. 74 N