I don't see any text to read with your question
"C", "Maybe".
The credibility depends on the websites contents and credentials.
A website like a government's page is considered, "credible", because it is from a trusted source; the government. Whereas getting a random answer from Yahoo is considered less credible because of it not stemming from a trustable source.
Hey, it's TeenSuicide.
A.Includes a brief summary of each sources content and focus
The correct answer is tone. Imagery is using vivid description while style is the personal type of narration like what words they use or grammatical constructions. Theme is the underlying idea while the voice is seen through the tone, whether it's dark and broody or joyful or anything similar.
I would go with C. Because the narrator is talking. The narrator want to have a lesson badly on water-reading. But Mr. Bixby thinks the narrator is far to advanced for it and will not teach her it. So Mr. Bixby is being stubborn and will not give the lesson.