TTGWD1-23

Q23:

For the first time in the modern era, non-Hispanic Whites are officially a minority in California, which amounts to a little less than half the population of the state, down from nearly there-quarters only a decade ago.

1. which amounts to a little less than half the population of the state, down from nearly three-quarters only a decade ago
2. which amounts to a little less than half the population of the state, down from a decade ago, when it was nearly three-quarters
3. and that amounts to a little less than half the population of the state, down from a decade ago, when they were nearly three-quarters
4. amounting to a little less than half the population of the state, down from nearly three-quarters a decade ago
5. amounting to a little less than half the population of the state, down from what it was a decade ago by nearly three-quarters

又在D和E中犹豫了，想问一下E错误的原因是什么？难道是from后不能用what吗？

这个是从句意判断出来的

D 占人口的比例从四分之三降到一半都不到

E10年前的比例降了四分之三，直至现在一半都不到

完全两个意思