The fact of me/ being a stranger/ does not excuse his conduct.

The correct answer is D. No error.

The sentence “The fact of me being a stranger does not excuse his conduct” is grammatically correct. The phrase “The fact of me” is a noun phrase that serves as the subject of the sentence. The verb phrase “being a stranger” modifies the noun “me.” The prepositional phrase “does not excuse his conduct” is the object of the verb “is.”

The sentence is clear and concise, and it conveys the intended meaning. There is no error in grammar, punctuation, or spelling.