In the equation: HF + H2 H3O+ + F-

(a) H2O is a base and HF is its conjugate acid.

(b) H2O is an acid and HF is the conjugate base.

(c) HF is an acid and F- is its conjugate base.

(d) HF is a base and H3O+ is its conjugate acid.

(e) HF is a base and F- is its conjugate acid.