The unit of temperature coefficient of resistivity is

Explanation

The coefficient is the fractional change in resistivity per unit rise in temperature, so the resistivity units cancel and only reciprocal temperature remains, giving per kelvin. Because a kelvin and a degree Celsius are the same size, per degree Celsius is numerically identical, which is why the first option is such a close distractor. Reciprocal ampere and reciprocal second belong to quite different quantities.