Among five friends J, K, L, M, N, each of different height, who is the second tallest? I. N is taller than M and K; K is shorter than M. II. L is taller than M and N; J is not the tallest.

Introduction / Context:
We must uniquely identify the second tallest using partial order information.

Given Data / Assumptions:

• I: N > M > K; no info on L, J.
• II: L > M and L > N; J is not tallest.

Concept / Approach:
Combine inequalities and see whether a unique second tallest emerges.

Step-by-Step Reasoning:
From I: N > M > K; positions of L and J unknown.From II: L is taller than both M and N; J is not tallest, but J’s relation to L and N is unknown.Together: L > N > M > K; J is somewhere below L but could be above or below N. If J is between L and N, second tallest is J; if J is below N, second tallest is N. Non-unique.

Why Other Options Are Wrong:
Neither I nor II alone suffices, and even together ambiguity remains.

Final Answer:
Neither statement alone nor both together are sufficient.