The last options seems right. the one that is " Trees that are not native to North Texas, are often killed by heat and drought. "
Interior isn't a type of narration. There's only third-person limited, and omniscient. No such thing as interior. The type you're missing is second-person narration.
The tone of a poem is the attitude you feel in it, the writer's attitude toward the subject or audience. In this case, this is a sad poem, so the line that best develops its tone would be Line 4, where specifically indicates the boy is no longer anymore.
send me a picture or a sentence in the comments so I can solve