3. Clicker training is a good way to teach behaviors that A. can't be elicited any other way.
B. are very involved.
O C. are difficult to lure.
D. the dog isn't good at.

rain is the best answer

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.