Series and parallel resistor combinations Steps:

• Maximum resistance occurs when all three resistors are connected in series: total R = R + R + R = 3R.
• Minimum resistance occurs when all three are connected in parallel: 1/R_min = 1/R + 1/R + 1/R = 3/R, so R_min = R/3.
• For R = 15 Ω, maximum = 45 Ω and minimum = 5.0 Ω.
• Other arrangements (e.g., two in series with one in parallel) yield values between 5 Ω and 45 Ω.

Why B is correct:

• Option B matches the series formula (3R = 45 Ω) and parallel formula (R/3 = 5.0 Ω) for three equal resistors.

Why the others are wrong:

• A: Underestimates maximum (15 Ω is two in series, not all three).
• C: Swaps min/max and ignores parallel reduction to 5 Ω.
• D: Overestimates minimum (15 Ω is a single resistor, not using all three in parallel).

Final answer: B