Providing background on the Renaissance would allow Charlie to talk about the shared history. This leads to talking about the effect the period had on art, and then specifically on the artists mentioned.
C. Paragraph 1: history of Renaissance; paragraph 2: effects of Renaissance on art; paragraph 3: effects of Renaissance on da Vinci, Michelangelo, and Raphael
I sharpened my skills under the mentorship of my coach. You need a noun to complete this sentence, and mentorship is the only noun here - the rest of the words are adjectives.
