What is a major challenge of current space exploration?

Adeveloping bigger rockets
Bsetting a clear goal for the future
Csending unmanned probes to other planets
Dsecuring international cooperation for missions

Verified Answer :

B. setting a clear goal for the futureĀ 

Answer:

B) Setting a clear goal for the future.

Explanation:

At this point in time, the future of space exploration is unclear. NASA is debating whether we should return to the Moon, or press on to Mars. (although it seems more likely that we will go to Mars some time in the future.)

(I took the quiz, and it was right.)