Jack and Jill have a certain number of apples with them. The total number of apples with both of them is less than 80. If Jill gives a certain number of apples to Jack, then Jack will have four times the number of apples Jill has. If Jack gives the same number of apples to Jill, then Jack will have thrice the number of apples that Jill has. What can be the number of apples that Jack initially has?

A. 31
B. 36
C. 45
D. 62
E. 63

Answer: A

Source: e-GMAT