PASCAL 2000 Problem 13

In the expression \frac ab+\frac cd+\frac ef each letter is replaced by a different digit from 1,2,3,4,5, and 6. What is the largest possible value of this expression?

Answer Choices
A. 8\frac23
B. 9\frac56
C. 9\frac13
D. 9\frac23
E. 10\frac13