1. We are running out of freshwater, ________?

The correct answer is d. aren't we.

*Explanation:*
This is a tag question. The main clause is positive ("We are running out of freshwater"), so the tag question should be negative. Also, the subject is "we", so the correct tag is "aren't we?".

*Translation:*
У нас заканчивается пресная вода, не так ли?