Use the Rational Zero Theorem to list all possible rational zeros for the given function.
f(x) = 9x^4 - x^3 + 4x^2 - 5x - 6.
Which of the following is the complete list of possible zeros of the given function?
a. ±1, ±3, ±2, ±1/3, ±2/3
b. ±1, ±3, ±2/3, ±1/9, ±2/9
c. ±1, ±3, ±2, ±6, ±1/3, ±2/3, ±1/9, ±2/9
d. The function has no rational zeros.