The air in st. thomas was humid and sticking to my skin. the hot beach made my toes burn as i walked to the edge of the sand. i could hardly believe the beauty of the ocean. i’d never seen water so clear and bright. the shore in new jersey was nice, but the waters of the atlantic always seemed very dark. this water sparkled like a diamond in the sunlight.

which of these choices best adds specific and concrete detail to the vague phrase seemed very dark in the passage?

a) seemed quite hard-to-see

b) seemed black and murky

c) seemed unpleasant

d) seemed very vague