Heights — Among A, B, C, D, E (all different heights), who is the third tallest? Statements: I. E is shorter than only B. II. C is taller than only A.

Introduction / Context:
We need the 3rd tallest given two partial order constraints among five distinct heights.

Given Data / Assumptions:

• I: E is below only B ⇒ B is tallest (1st), E is 2nd.
• II: C is above only A ⇒ A is 5th (shortest), C is 4th.

Concept / Approach:
Merge the two chains to place the remaining person (D).

Step-by-Step Solution:

Verification / Alternative check:
Distinctness is respected; no conflicts arise.

Why Other Options Are Wrong:

• A/B/C: Either statement alone does not fix the 3rd position.
• E: Although the combination is sufficient, the wording 'necessary' highlights that neither alone suffices; the classification corresponds to needing both.

Common Pitfalls:
Misplacing C above E; ignoring that II fixes bottom two strictly.

Final Answer:
D — Both statements together are necessary (3rd tallest is D).