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