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

答案是D。我猜了个E。不明白两者差异。

AB与DE之间进行有什么原则吗？

ab先行词which只能修饰California，句意不通；只可从de中选择，e项本身冗余且有歧义，应该是从3/4降到<1/2,e项用by表明从十年前降了3/4到目前的<1/2.