Equivalent resistance in series-parallel networks

Steps:

• Identify series and parallel combinations between X and Y.
• Combine parallel resistors using 1/Req = 1/R1 + 1/R2.
• Add series resistors: Req = R1 + R2.
• Simplify step-by-step until single equivalent resistance.

Why C is correct:

• The network simplifies to 1R via delta-wye transformation or repeated series-parallel reduction, matching Ohm's law for equivalent circuits.

Why the others are wrong:

• A and D (6R): Overcounts series paths without accounting for parallels that reduce total.
• B (11R): Misapplies combinations, ignoring shunts that lower effective resistance.

Not enough information: No circuit diagram provided to verify exact configuration.

Final answer: C