If n is an odd integer, which one of the following is an even integer?

Explanation

A is incorrect as assuming our odd integer is 3, cube of 3 is equal to 9, which is not even. B is incorrect as assuming our odd integer is 3, 3/4 is equal to 0.75, which is not even or neither an integer. C is incorrect as assuming our odd integer to be 3, {2(3) + 3 = 9}, which is not even, D is correct as assuming our odd integer to be 3, {3(3)+3 = 12}, which is even and an integer.