I think the answer might be C.
Step-by-step explanation:
That is because if you look at C, it is -8 + 3a + 10 - a. Since it says -a, it means you have to subtract 3a - a = 2a, since a variable equals one in algebra. Then all that is left is -8 + 10, which will give you 2, which will give you 2a + 2. Hope this helps.
