f(x) = − 2x3 + x2 + 16x − 15 and g(x) = x + 3

We can use synthetic division to divide it
x+3=0 or x=-3
So
-3__ |____-2 ____ 1 ____ 16 ____ -15
___ | _________6 ____-21 ____15
______________________
_______ -2____7____ -5 ____0
So the expressions should be

That is Option B