Which of the following resistive materials has the lowest temperature co-efficient of resistance ?

Answer: Option B

Temperature coefficient of resistance (TCR) indicates how much the resistance of a material changes with temperature.

A material with a low temperature coefficient shows very little change in resistance when temperature varies, which is desirable for precision resistors and measuring instruments.

Constantan has an extremely low and nearly zero temperature coefficient of resistance compared to other resistive materials listed.

Nichrome and Kanthal have higher temperature coefficients and are mainly used for heating elements where resistance change is acceptable.

Molybdenum is a metal with a relatively high positive temperature coefficient of resistance.

Therefore, the resistive material with the lowest temperature coefficient of resistance is Constantan.