Which sentence uses desolate correctly? A. We used sticks gathered in the woods to build a toasty, desolate fire.

B. Yoga provides feelings of desolate and calm, which benefits practitioners.

C. During the war, entire cities were reduced to desolate piles of rubble.

D. The stadium was so crowded and desolate that I could hardly move.

The answer would be C: During the was, entire cities were reduced to desolate piles of rubble

Explanation:

This is correct because the definition of desolate is "deserted of people and in a state of bleak and dismal emptiness." And "bleakly and depressingly empty or bare"

the answer should be d) he was one of those young thousands who greeted the war with a certain amount of relief, welcoming the liberation from webs of tangled emotion" since it is the best option because it shows his desire to free himself. 

hope this answer you! have a great day.