Question

what does the idiom in this text suggest? cell phones once cost an arm and a leg, but today the majority of people can afford them. cell phones once varied greatly in price. cell phones were once popular items to trade. cell phones were once very expensive.

Explanation:

The idiom "cost an arm and a leg" means something is very expensive. In the sentence, it's used to describe cell phones' past price, and the contrast with today's affordability supports that they were once very expensive. The first option is about price variation (not what the idiom means), and the second is about trading popularity (unrelated to the idiom's meaning).

Answer:

Cell phones were once very expensive.