If a is even, b is odd, and a^2 + b^2 = x which of following must be t

If a is even, b is odd, and \(a^2 + b^2 = x\) which of following must be true? A. x is the square of an integer. B. x is odd. C. x is a multiple of a. x D. is prime E. \(a^2 + b^2 = x\)