Let X1, X2, . .., Xn be a random sample from a normal distribution N(u, 36). Find the best critical region for testing Ho : M = 80 against Ha : M = 76 when n = 16 and a = 0.05. O a. RR = {(x1, . . ., "'16) : x > 77.5325} O b. RR = {(1, . . ., '16) : x