Concept:The correct word depends on whether we are making a negative statement about two people or choosing between options.
Explanation:• The sentence is negative: "couldn't get into the house".
• We need a negative construction for two people: Mohan and I.
• "Neither" means "not either" and is used to make a negative statement about two persons or things.
• Structure: "neither of + pronoun (us)" + verb in affirmative form.
• "Neither of us had the keys" is correct because "neither" already carries the negative meaning, so the verb "had" is affirmative.
• Option A: "neither of us had the keys" – correct.
• Option B: "both of us do not have the keys" – wrong because "both" is positive and we need a negative sense; also tense mismatch with "couldn't".
• Option C: "either of us did not have the keys" – "either" suggests a choice between two, not a negative of both.
• Option D: "neither of us did have the keys" – incorrect because "neither" already provides negation; "did have" is emphatic but not needed here.
• Therefore, only option A fits the grammar and meaning.
Answer:A. neither of us had the keys