Seven members in a row – who sits exactly in the middle? Constraints (left-to-right ordering): C is left of B but right of D (D … C … B). A is right of B. F is right of E but left of D (E … F … D). H is left of E.

Introduction / Context:
We have seven distinct members with multiple “to the left/right of” constraints. The goal is to determine who occupies the central (4th) position when everyone is arranged left to right.

Given Data / Assumptions:

• D … C … B (C is between D and B, with C left of B).
• A is to the right of B ⇒ B … A.
• E … F … D (F is right of E but left of D).
• H is left of E ⇒ H … E.

Concept / Approach:
Chain the inequalities to form one consistent sequence. From E … F … D and H … E, we get H … E … F … D. From D … C … B and B … A, extend to the right: … D … C … B … A.

Step-by-Step Solution:

Verification / Alternative check:
Any attempt to move D left of F breaks “F left of D”; moving C left of D breaks “D left of C”; placing A to the left of B breaks “A right of B.”

Why Other Options Are Wrong:
C, E, F are not at the 4th position in any arrangement that honors all constraints.

Common Pitfalls:
Not chaining all relations together and overlooking that the set H, E, F, D must precede C, B, A in that order.

Final Answer:
D