The answer depends on someone who would most impartial, meaning not having an opinion that could change because of money (question 3), would need to have some knowledge of the lake (question 2) and would not alter results to avoid implicating the coal mine (question 1). The best choice is 1 because this person uses the water, but would not be affected economically by discussing the lake and the coal mine. Number 3 is the second best choice because they have answered no to all three questions. The reason Number 3 is not the best choice is because they do not regularly use the water, unlike Number 1.