If p and q are prime numbers, how many divisors does the product p^4 * q^5 have? Choose the correct option.
A) 30
B) 40
C) 45
D) 50
E) 56

Rationale: when a number n = a ^ x * b ^ y , where a and b are prime numbers , and x , y are positive integers , the number of divisors of n = ( x + 1 ) ( y + 1 ) therefore , the answer is a . 5 * 6 = 30
Answer: A