The correct answer is 'its way of challenging social norms'. Because in this play, a woman decides to leave her husband and children, which was, of course, unacceptable at the time.
A Doll's House discusses the traditional 19th century marriage. What Ibsen did in the play was considered controversial during those times. The play became significant for the depiction a woman's lack of opportunity in finding her place in a male-dominated society. Because of its criticism of social norm during that time it became so popular, but also controversial at the same time.
It describes the lightning as "dancing" which is a human trait, so when objects other than people and animals do human-like things, it's personification.
