Q: In this task, you are given two facts, and a multiple-choice question. Based on the given facts, answer the question with index of the correct option (e.g, "A").
Fact1: damming a river can cause a lake to form, Fact2: Beavers build dams that create ponds., Question: What can be the cause of lakes and ponds forming? (A) beavers (B) heat (C) Pesticides (D) flooding (E) erosion (F) rainfall (G) loose soil (H) spring
A:
A