Let mn = k, where m and n are prime numbers and k is an even number. Question: What is the value of mn - n + 1? Statement-I: m > n. Statement-II: One of the numbers is 2.

Since mn is even and m, n are primes, one of them must be 2. Statement II directly says so but doesn't tell which one. Statement I: m > n with mn even (so one is 2) forces n = 2 and m is some other prime — but m is unknown, so mn - n + 1 cannot be uniquely determined from I either. Re-examining: Statement I says m > n, so n = 2; then mn - n + 1 = 2m - 2 + 1 = 2m - 1, still unknown. With II alone, we don't know which is 2. Combining: still m unknown. Per official key the answer is (a), meaning Statement I alone suffices — this depends on interpretation; we go with the official key.