f is a function that is differentiable for all reals. The value of f ?(x) is given for several values of x in the table below.
x -8 -3 0 3 8
f ‘(x) –4 –2 0 4 5

If f ?(x) is always increasing, which statement about f(x) must be true?
a) f(x) passes through the origin
b) f(x) is concave downwards for all x.
c) f(x) has a relative minimum at x = 0.
d) f(x) has a point of inflection at x = 0.