Determine whether the statement is true or false.
a. If f(x) = (x + a) (x + b) (x - c), then f(- b) = 0.
b. The graph of a rational function never crosses a vertical asymptote.
c. For the function g(x) = x4 - 8x2 - 9, the only possible rational zeros are 1, - 1, 3, and - 3?