Which excerpt from O'Connor's "Good Country People" contains an example of irony?

The excerpt that contains an example of irony is letter B. "When she and the girl happened to be out of the house together, she would say something and add the name Hulga at the end of it, and the big-spectacled Joy Hulga would scowl and redden as if her privacy had been intruded upon. She considered the name her personal affair."