Let P(n) and S(n) denote the product and the sum, respectively, of the digits of the integer n. For example, P(23)=6 and S(23)=5. Suppose N is a two-digit number such that N=P(N)+S(N). What is the units digit of N ?
Answer Choices
A. 2
B. 3
C. 6
D. 8
E. 9