Question

docs.google.com/document/d/1z7NpDHYFABc6rvHOcE_io3zx0JKYhXhDqGyPpzPEzwI/edit

A question with a graph on it

Answer 1

y = (x-a)(a-b) crosses the x-axis at a and b.

so y <= 0 between the roots.
Choice B is the one you want, since b < a
That makes the signs of the two factors opposite, and their product is negative.