If x and y are prime numbers, which of the following CANNOT be ( x + Y )? Choose the correct option.
A) 5
B) 23
C) 13
D) 16
E) 3
All answer choices but B are odd. In order odd number to be the sum of two prime numbers one must be even, so 2, and another odd.   Now, 23=2+21. Since 21 is not a prime then 23 cannot be written as the sum of two prime numbers.   Answer: 23
<result>B</result>
If x and y are prime numbers, which of the following CANNOT be ( x + Y )?