Richard needed to read 5 books for his summer reading assignment. It took him 4 5/8 hours to read the first 2 books. It took him 7 7/8 hours to read the remaining 3 books. How long did it take Richard to read all 5 books?
A. 11 4/8 hours
B. 11 6/8 hours
C. 12 4/8 hours
D. 12 6/8 hours