The answer you are looking for is A. Coefficient.
A coefficient is a number that is in front of a variable. Examples of this are 6 in 6x, 100 in 100s, and 45 in 45h. Thus making 8 the coefficient of the problem.
There are also no like terms (like 4 and 6 or 5x and 9x), there is no inequality sign (greater than, less than, etc), and there are no constant variables (like 2 and 7 in the equation " 2x - 2 = 7).
I hope this helps!