It looks like the parabola are going down, so the coefficient should be negative,
B or C,
then we see that the parabola has x -intercepts (1,0) and (5,0)
these roots should be written as multiples
x=1, so x-1=0
and
x=5, so x-5=0,
so (x-1)(x-5) and negative first coefficient -2 at the same time.
We can see only in the
B. f(x) = –2(x – 5)(x – 1)