Let $a$ and $b$ be integers,
$$a ^ { 2 } + a b + a + b$$
It is known that this number is odd.
Accordingly,
I. a
II. $\mathrm { a } + \mathrm { b }$
III. ab
Which of these numbers are even?
A) Only I
B) Only II
C) I and III
D) II and III
E) I, II and III