What is ironic about what happens to Hauchecorne in "The Piece of String"?

AHe needed some string and then happened to find some.
BHis friend Malandain turns against him rather than standing up for him.
CHis reputation for clever dealing betrays him when he tells the truth.
DHe lives in a town full of thieves and then becomes one.

Verified Answer :

Answer: C. His reputation for clever dealing betrays him when he tells the truth.

The statement in letter c shows irony because it presents contrasting events. Mr. Hauchecorne is a clever person  however the irony strikes on him when nobody believes him and makes fun of his cleverness when he said the truth about the string.