The two quotes that best support the sentence by describing the narrator's anxiety and fear are:
A) "And every night, about midnight, I turned the latch of his door and opened it-oh, so gently!"
B) "I moved it slowly-very, very slowly, so that I might not disturb the old man's sleep."
These quotes highlight the narrator's meticulous and cautious actions, which reflect his anxiety and fear regarding the old man's reaction and his own mental state.