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.
- the short flights of the shuttle and earlier spacecraft, which carried sufficient power in fuel cells and batteries
- the shuttle and earlier spacecraft, with sufficient enough power in fuel cells and batteries for their short flights
- the short flights of the shuttle and earlier spacecraft, which enabled them to carry sufficient enough power in fuel cells and batteries
- the shuttle and earlier spacecraft, which were capable of carrying sufficient power in fuel cells and batteries for their short flights
- the flights of the shuttle and earlier spacecraft, whose shortness allowed them to carry sufficient power in fuel cells and batteries
The answer is D, I choose B, why? |