If x is a sum of all even integers on the interval 13...45 and y is their number, what is the GCD (x, y)?  Choose the correct choice from the following answers:
A) 1 B) 16 C) 26 D) 52 E) 1014
x = 14 + 16 + ... + 44 = (largest + smallest)/2 *(# of terms) = (14 + 44)/2*16 = 29*16.   GCD of 16 and 29*16 is 16.   Answer: 16.
<result>B</result>
If x is a sum of all even integers on the interval 13...45 and y is their number, what is the GCD (x, y)?