In a park there are two ponds with both brown ducks and green ducks. In the smaller pond there are 20 ducks and in the larger pond there are 80 ducks. If 20% of the ducks in the smaller pond are green and 15% of the ducks in the larger pond are green, then what percentage of ducks are green?
Choose the correct choice from the following:
A) 13 %
B) 14 %
C) 15 %
D) 16 %
E) 17 %

Rationale: "number of ducks in small pond = 20 green ducks in small pond = 20 % of 20 = 4 ducks number of ducks in large pond = 80 green ducks in large pond = 15 % of 80 = 12 ducks total number of ducks = 20 + 80 = 100 total number of green ducks = 4 + 12 = 16 ducks percentage of green ducks = 16 / 100 * 100 = 16 % answer : d"
Answer: D