If a and b are unique prime integers, which of the following must be even? Choose the most appropriate option
A) a−b
B) a−2b
C) 2a−2b
D) 2a−b
E) ab^2
Let's assume that a is an even prime integer and b is an odd prime integer, their subtraction results in an odd integer and an odd integer multiplied by an even integer yields an even integer.   Answer 2a−2b
<result>C</result>
If a and b are unique prime integers, which of the following must be even?