The dam holds water of depth 4 m on one side. The width of the dam is 8 m. Neglecting the weight of the dam, what are the reactions at A and B?
A) A: 0 N, B: 0 N
B) A: 80 N, B: 40 N
C) A: 40 N, B: 80 N
D) A: 0 N, B: 40 N