ttgwd15-30

Unlike the short flights of the shuttle and earlier spacecraft, which carried sufficient power in fuel cells and batteries, a permanently orbiting space station will have to generate its own electricity.

1. the short flights of the shuttle and earlier spacecraft, which carried sufficient power in fuel cells and batteries
2. the shuttle and earlier spacecraft, with sufficient enough power in fuel cells and batteries for their short flights
3. the short flights of the shuttle and earlier spacecraft, which enabled them to carry sufficient enough power in fuel cells and batteries
4. the shuttle and earlier spacecraft, which were capable of carrying sufficient power in fuel cells and batteries for their
                       short flights
5. the flights of the shuttle and earlier spacecraft, whose shortness allowed them to carry sufficient power in fuel cells and batteries

答案是d,可那个their指什么?是spacecraft吗?spacecraft就是复数吗?

请指教

没人理我

请教

If B, with has fuzzy meaning since we may understand the logical subject of "with" is "a permanently orbiting space station ", and this understanding is illogical. That is my understanding "with" is not a really preferable answer.

Anyone has some complete explanation about the usage of with/that/which? thx

And also, sufficient and enough are redundent. so B definitely wrong