Which excerpt reflects a second-person point of view?
After he had dried his face and not knowing what else to do dried it again, the boy turned around, wondering what next. The door was open. He could make a dash for it down the hall. He could run, run, run, run, run! (Langston Hughes, “Thank You Ma’am”)
Always obey your parents, when they are present. This is the best policy in the long run, because if you don’t, they will make you. (Mark Twain, “Advice to Youth”)
They stopped running and stood in the great jungle that covered Venus that grew and never stopped growing, tumultuously, even as you watched it. (Ray Bradbury, “All Summer in a Day”)
The children lay out, laughing, on the jungle mattress, and heard it sigh and squeak under them resilient and alive. (Ray Bradbury, “All Summer in a Day”)
"In my time," said the grandmother, folding her thin veined fingers, "children were more respectful of their native states and their parents and everything else." (Flannery O’Connor, “A Good Man Is Hard to Find”)

Answer: B: Always obey your parents, when they are present. This is the best policy in the long run, because if you don’t, they will make you. (Mark Twain, “Advice to Youth”)

Explanation

In the first one the “Thank You Ma’am”, Langston used "he, the boy,..." and also showed the character's thought "After he had dried his face and not knowing what else to do dried it again; He could make a dash for it down the hall, ...". So that we know it's the third-person-omniscient POV.

In the second one, Mark Twain used the words "your, you" so we know it is the second-person POV.

In the third one, although the narrator used the word "you", he put it in the phrase " even as you watched it." That's mean he's putting you into the character's POV, meaning that if you were there, you'll do the same as the characters.

In the fourth one, the narrator used "The children, them" so we know it's a third-person POV.

And the last one, the narrator shown us the conversation between the characters, and also express their act, so it is third-person-limited/omniscient POV.

So, extruding those third person somethings..., the Mark Twain, “Advice to Youth” is the second-person POV.