Answer:
D
Explanation:
Well, I had to think about this one. It could have been A, but when I went over the definition of monstrous it meant a couple of things, one of them was large, the other one was horrible. Then I went to monstrosity. It only had one meaning large or unsightly. So I finally disclosed on D. I am very very very sorry if I got this wrong :(. Great luck. :D
Participles are words formed from verbs that can be used as adjectives. In this sentence, "roaring" would be B, participle.