Why is Hauchecorne's surprise at his neighbors' reactions to his claims of innocence ironic?

AHauchecorne knows his reputation and should not expect to be trusted.
BHauchecorne knows that Malandain is just trying to get even with him.
CHauchecorne knows that Malandain witnessed him pick up the string.
DHauchecorne knows that the wallet has been found and will soon be turned in.

Verified Answer :

d. Hauchecorne knows that the wallet has been found and will soon be turned in.

Why is Hauchecorne's surprise at his neighbors' reactions to his claims of innocence ironic?
Hauchecorne knows that the wallet has been found and will soon be turned in.

NOT:


a. Hauchecorne knows his reputation and should not expect to be trusted.
b. Hauchecorne knows that Malandain is just trying to get even with him.
c. Hauchecorne knows that Malandain witnessed him pick up the string.