If {x} is the product of all even integers from 1 to x inclusive, what is the greatest prime factor of {18} + {16}?  Choose the correct choice
A) 23  B) 20  C) 11  D) 19  E) 2

Rationale: soln : { 18 } + { 16 } = 18 * { 16 } + { 16 } = 19 * { 16 } answer : d
Answer: D