A painter completed five jobs in a period of 40 3/4 working hours. If four of the jobs took 5 hours, 91/4 hours, 81/2 hours, and 5 hours. How long did it take the painter to complete the fifth job?
A. 12 hours
B. 12 3/4 hours
C. 13 hours
D. 13 3/4 hours