Insufficient information to determine combined resistance

Steps:

• Identify components: thermistor at 10°C in series with 20Ω fixed resistor.
• Recall series formula: total R = R_thermistor + R_fixed.
• Note missing data: thermistor resistance at 10°C not provided.
• Conclude: cannot calculate total without thermistor value.

Why D is correct:

• Not applicable; no calculation possible due to missing thermistor resistance.

Why the others are wrong:

• A: Assumes thermistor resistance of -4Ω, impossible for resistors.
• B: Ignores thermistor, only fixed resistor value.
• C: Assumes thermistor of 60Ω, but no basis for this.

Not enough information.

Final answer: Not enough information.