Which part of this is an idiom I'm not sure about Perkins said the director I don't think he's company material I have reservations too said Drucker but I can't quite put my finger on it?

The full question is:

Question: Which part of the paragraph below is an idiom?

"I'm not sure about Perkins," said the director. "I don't think he's company

material."

"I have reservations, too," said Drucker, "but I can't quite put my finger on it."

"Here's my two cents: I don't think he plays Golf."

"Not a golfer?" Drucker's mouth gaped in amazement. "Well, I think you've hit

the nail on the head, sir."

A. Put my finger on it

B. My two cents

C. Hit the nail on the head

*D. All of the above

*D. All of the choices are correct.