Today’s technology allows manufacturers to make small cars more fuel-efficient now than at any time in their production history.
- small cars more fuel-efficient now than at any time in their
- small cars that are more fuel-efficient than they were at any time in their
- small cars that are more fuel-efficient than those at any other time in
- more fuel-efficient small cars than those at any other time in their
- more fuel-efficient small cars now than at any time in [C]
请问D项比较得对象是什么？是不是manufacutures | 
