Identify conjugate acid and conjugate base in the following reaction.
H2PO4− (aq) + H2O (l) ⇌ HPO42− (aq) + H3O+ (aq)
a) HPO42− (conjugate acid), H3O+ (conjugate base)
b) HPO42− (conjugate base), H3O+ (conjugate acid)
c) H2PO4− (conjugate acid), H2O (conjugate base)
d) H2PO4− (conjugate base), H2O (conjugate acid)