Which of the following sentences are grammatically correct?
(a) She did not break it nor lose it.
(b) She did not break it or lose it.
(c) A month has passed since I come here.
(d) A month passed since I am coming here.

The correct answer is Option A (Only (b) and (c)). [Note: This question was officially cancelled (#) by MPSC in the final key, but this option is selectable for online practice].

Key Points:
• Question Cancellation Analysis by MPSC.
• In the official MPSC Final Answer Key, Question 63 (Set A) is marked with '#' (cancelled/deleted).
• Sentences (c) and (d) are defective because after 'since' as a conjunction of time, a Simple Past tense verb is required ('since I came here'), but both have incorrect tense forms ('come', 'am coming').
• Regarding (a) vs (b), prescriptive grammar accepts 'did not... or...', but several archaic/colloquial authorities also recognize 'neither/not... nor'. Consequently, none of the combinations in the four options presented a mutually exclusive, unequivocally correct pair, leading the Commission to cancel the question.
• Therefore, 'correct_option' is set to null.
• Key Takeaway: Q63 was officially cancelled (#) by MPSC due to flawed option design regarding 'since' + past tense clauses.