A battery of electromotive force (e.m.f.) 
and negligible internal resistance is connected to a fixed resistor of resistance 
and a thermistor of resistance 
, as shown.
Initially, the temperature of the thermistor is 
and the current in the circuit is 
. The temperature of the thermistor then changes, which causes the current to increase to 
. How does the temperature of the thermistor change and what is RT at the new temperature?
. (Option A)
