Question

which line from \lather and nothing else.\ best reveals internal conflict?
to cover my nervousness, i went on honing the razor.
he evidently took it for granted that i was on the side of the existing regime.
he looked younger, several years younger than when he had come in.
and it would be so easy to kill him. he deserves it. or does he? no!

Explanation:

Internal conflict is a struggle within a character's mind. The line "And it would be so easy to kill him. He deserves it. Or does he? No!" shows the barber's internal struggle (conflict) about whether to kill the captain. The other lines do not show such a mental struggle. The first line shows nervousness (an emotion but not a conflict of ideas/values), the second line is about the captain's assumption, and the third line is about an observation of appearance.

Answer:

And it would be so easy to kill him. He deserves it. Or does he? No!