If x, y, and z are consecutive odd integers, with x < y < z, then which of the following must be true?
I. x + y is even
II. (x+z)/y is an integer
III. xz is even  Pick one:
A) I only
B) II only
C) III only
D) I and II only
E) I, II, and III
x, y, and z are consecutive integers ⇒   Y = X+2   Z = X+4   1- x+y is even - Correct: sum of any 2 odd integers is even   2- (x+z)/y is an integer - Correct: x+z = x+x+4 = 2x+4 = 2(x+2)   and x+z/y = 2(x+2)/x+2 = 2 ⇒ integer   3- xz is even - Not Correct: multiplication of any 2 odd integers is always odd   Answer: I and II only
<result>D</result>
If x, y, and z are consecutive odd integers, with x < y < z, then which of the following must be true?
I. x + y is even
II. (x+z)/y is an integer
III. xz is even