Final answer:
In 'Fahrenheit 451,' Guy Montag knew Clarisse McClellan, who inspired him with her reflective thoughts, and Professor Faber, who mentored him in understanding literature's importance. The correct option is A.
Step-by-step explanation:
In Ray Bradbury's Fahrenheit 451, two people that Guy Montag knew are a) Clarisse McClellan and Faber. Clarisse is a young neighbor who introduces Montag to a world of ideas and reflective thought, sparking his rebellion against a society that burns books and discourages intellectualism.
Professor Faber is an English professor who becomes Montag's mentor and helps him understand the importance of literature and the need to preserve it.