What is the difference between PTC and NTC thermistor?

Select one alternative:

NTC thermistor resistance increases linearly with increase of temperature, while in PTC

resistance drops linearly with increase of temperature

PTC thermistor resistance is dropping linearly with increase of temperature, while in NTC

resistance increases linearly with increase of temperature

NTC thermistor resistance is dropping nonlinearly with increase of temperature, while in

PTC resistance increases nonlinearly with increase of temperature

PTC thermistor resistance is dropping nonlinearly with increase of temperature, while in

NTC resistance increases nonlinearly with increase of temperature