For some integer , every even integer is of the form
Step 1: Explanation for correct option.
For option B:
For , which is even.
For , which is even.
For , which is even.
Thus for some integer and so on, which are all even.
So, option B is correct
Step 2: Explanation for incorrect option.
For option A:
For , which is odd.
For , which is even.
For , which is odd.
So, option A is incorrect
For option C:
For , which is odd.
For , which is odd.
So, option C is incorrect
For option D:
For , which is odd.
For , which is odd.
Therefore, for some integer , every even integer is of the form
So, option D is incorrect
Hence, correct option is (B).