GWD语法题！求解！

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

请问E为什么错，正确答案是C

我也不懂.

顶!!!!!!!

E中，it 無指涉對象

less 是 little 的比较级别，与不可数名词连用，，

less time，suger 等，，文中涉及的比较是可数名词，，ADE全排除