Read the passage from A Room of One’s Own.

The history of men's opposition to women's emancipation is more interesting perhaps than the story of that emancipation itself. An amusing book might be made of it if some young student at Girton or Newnham would collect examples and deduce a theory,—but she would need thick gloves on her hands, and bars to protect her of solid gold.

Which rhetorical device is used in this text?

irony alliteration
alliteration
overstatement
understatement