Compute the following probabilities by using the hyper-geometric formula.

a. The probability of x = 3 if N = 11, A = 8, and n = 4

b. The probability of x < 2 if N = 15, A = 5, and n = 6

c. The probability of x = 0 if N = 9, A = 2, and n = 3

d. The probability of x > 4 if N = 20, A = 5, and n = 7