Bill has worked for White Drywall for 4 years. During this period White Drywall has contributed $25,000 to her non-contributory retirement plan. Assuming BC uses cliff vesting, the longest period allowed, how much will Jamie be able to roll into an IRA if she left ABC printing?

A. $0

B. $5,000

C. $10,000

D. $15,000

E. $20,000

On the worksheet the answer is D. How do you work the problem out to get this answer ?