15.

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

flying down the mountain through untouched snow. It is the answer to the previous question.

Item B/D: Down the mountain is a prepositional phrase, which cannot be separated by commas, and item B/D is wrong.

A item: Through untouched snow is a prepositional phrase, which cannot be separated by commas, and item A is wrong.