Let f(x, y) and h(x) differ an tiable functions are given such that f(x,y) dy = h(x) and Sh(x) dx 12. According to the below graph, if A/2, A, 2A, 3A represents the area of the given regions, what is the result of the integral f(x, y) dx dy t 1A/21 2 3 2A hod C) 18 21. E) 20