Answer:
Elemental sulfur is used in black gunpowder, matches, and fireworks; in the vulcanization of rubber; as a fungicide, insecticide, and fumigant; in the manufacture of phosphate fertilizers; and in the treatment of certain skin diseases. The principal use of sulfur, however, is in the preparation of its compounds.
C or d both are good but I am leaning towards c
First, it signals the end of Bill and Mary's attempt at conversation, startling Mary into the present.
If the lights symbolize truth or revelation, then their sudden brightness represents the irrefutable passage of time and the impossibility of ever recovering or re-doing the past. That the lights run "the whole length of Fifth Avenue" further emphasizes the completeness of this truth; there is no way to escape the passage of time.
It's worth noting that the lights turn on right after Bill says, "You ought to see my kids" and grins. It's a surprisingly unguarded moment, and it's the only expression of genuine warmth in the story. It's possible that his and Mary's children might represent those lights, being the brilliant chains that link the past with an ever-hopeful future.
B. feels, an action verb has to be an action that is happening, and is the subject of the sentence, so here it would be feels.
