Let m and n are positive integers. Then (A) If n ≠ 1, then m < mn. (B) If k is…

Evaluate each statement:

• If n ≠ 1, then m < mn. Reason: m and n are positive integers, so n ≥ 2 when n ≠ 1, giving mn ≥ 2m > m. This statement is true.

• If k is composite, then k = mn where 1 < m, n > k. Reason: This claims both factors exceed k, which is impossible because two integers greater than k cannot multiply to k. This statement is false.

• If mn = 1, then m = 1 and n = 1. Reason: With m and n positive integers, the only way their product is 1 is m = n = 1. This statement is true.

• If k is composite, then k = mn where 1 < m, n < k. Reason: By definition of composite, k has nontrivial divisors m and n greater than 1 and less than k. This statement is true.

Conclusion: The true statements are: "If n ≠ 1, then m < mn", "If mn = 1, then m = 1 and n = 1", and "If k is composite, then k = mn where 1 < m, n < k".

Therefore the correct choice is the option that lists those three true statements.