Yuan finds the sum of 3/10 + (1/5 + 1/10). Then he adds 1/15 to the sum. What is Yuan’s final sum?

A. 3/5

B. 1/5

C. 1/3

D. 2/3

3/10 + (1/5 + 1/10) = 6/10 = 3/5

3/5 + 1/15 = ___