Answer
(a) Yes
(b) No
(c) No
(d) Yes
(e) No
Work Step by Step
A conjugate acid-base has only one $H^+$ as a difference.
To check this description, take the acid and write its reaction:
(a) $HCO_3^-(aq) + H_2O(aq)$ $CO_3^{2-}(aq) + H_3O^+(aq)$
As we can see, we get $CO_3^{2-}$, so $HCO_3^-$ is its conjugate base.
But, if the result is different:
(b) $HSO_3^-(aq) + H_2O(aq)$ $SO_3^{2-}(aq) + H_3O^+(aq)$
$SO_3^{2-} \ne SO_4^{2-}$, so they are not a conjugate acid-base pair.
