求助GWD21-13,到底选什么？

sunny0625

Q13:

When drive-ins were at the height of their popularity in the late 1950’s, some 4,000 existed in the United States, but today there are less than one-quarter that many.

 

1. there are less than one-quarter that many
2. there are fewer than one-quarter as many
3. there are fewer than one-quarter of that amount
4. the number is less than one-quarter the amount
5. it is less than one-quarter of that amount

大家讨论下，答案到底是什么？

ljc0729

C吧