Answer:
D.) It is used as a verb to describe the main action of the sentence.
Explanation:
Shrieking is a verb because it is an action, it wouldn't be a verb if it was shrieked but in this case it is ending with <em>-ing</em>, therefore the action is taking place at the moment.
Hope this helps and if the explanation is unclear, I apologize.
The protagonist is most likely to experience a change in the climax
