If f is an even function that is continuous on [-1, 3] and if Jif(t) dt = 4 and [, f(t) dt = 8, then So f(t) dt = a) 0 1 - 3 = 4 3 b) 2 8 c) -2 -1 - 1 = 4 d) 4 e) None of the above