If {x} is the product of all even integers from 1 to x inclusive, what is the greatest prime factor of {12} + {10}?  Choose the correct choice from the following options
A) 23
B) 20
C) 13
D) 5
E) 2

Rationale: "soln : { 12 } + { 10 } = 12 * { 10 } + { 10 } = 13 * { 10 } answer : c"
Answer: C