If x is an integer, which of the following must be an even integer?  Choose the correct choice.
A) x^2-x-1
B) x^2-4x+6
C) x^2-5x+5
D) x^2+3x+8
E) x^2+2x+10
Check the options by plugging in some values ( Preferably smaller integers like 1 and 2 )   A: x^2-x-1 = -1 { If x = 1 }   B: x^2-4x+6 = 3 { If x = 1 }   C: x^2-5x+5 = 1 { If x = 1 }   x^2+3x+8: x^2+3x+8 = 12 { If x = 1 } &amp; x^2+3x+8 = 18 { If x = 2 }   E: x^2+2x+10 = 13 { If x = 1 }   Thus the only possible answer is (x^2+3x+8)
<result>D</result>
If x is an integer, which of the following must be an even integer?