Equivalent resistance between points determines current

Steps:

• Identify the network as a balanced Wheatstone bridge with equal resistors (assume 1Ω each for calculation).
• Compute Req for PQ: two 1Ω in parallel = 0.5Ω (smallest).
• Compute Req for PR: full bridge diagonal = 2Ω (largest, unbalanced path).
• Compare: largest I for smallest Req (PQ), smallest I for largest Req (PR).

Why B is correct:

• Matches lowest Req (PQ, direct parallel) and highest Req (PR, series-dominant diagonal) per Ohm's law (I=V/Req).

Why the others are wrong:

• A: QR has moderate Req (~1Ω), not largest.
• C: RS has low Req (~0.5Ω), not largest current; PR correct but mismatched.
• D: QS has moderate Req (~1Ω), not smallest current.

Final answer: B