Answer the following question: Fact 1: Sinkholes are formed by precipitation. Fact 2: Most of the precipitation is in the form of snow. Given the two facts above, sinkholes can be formed by?

Pick your answer from:
(1). rivers;
(2). snow;
(3). magma;
(4). sun;
(5). storms;
(6). rain;
(7). wind;
(8). fronts;
Answer:
(2).