Answer: A.
Explaniton:
Although you might not want to speak publicly about your project, if you do good enough you'll be rewarded! We aren't rewarded when actually speaking with people, but its good to know you did well because that'll make you more confident to talk to others just the same way.
"Like sparks from a blacksmith's window" refers to the sparks that happen when a blacksmith is working. The meaning depends on the context. The context should usually be something like anger, exploding anger, or it could be excitement...
The correct option is B.
In the sentence in option B, the narrator is appealing to the feelings of others, that is, he was looking for compassion. He was creating a relationship between himself and the others by saying that everyone has in one time or the other commit sin.