As the temperature of a conductor increases, its resistivity and conductivity change. The ratio of resistivity to conductivity.

Formula used : Resistivity is given by

Where is the resistivity

σ is the conductivity

When temperature of a conductor is increases, its resistivity will increase and conductivity will decrease.

Ration of resistivity to conductivity is

Conclusion : When the temperature of conductor increases, the ratio of resistivity to conductivity will increase. Option A is correct.