problem with temperature

In an equipment there is an insulated box, which is having a heating coil. it is used to treat chemicals at 45 degree Celsius.

now problem is, i am cutting off the power supply to the heating coil when the temperature inside the box is exactly 45 degree Celsius. box is well insulated. in this condition what would be the temperature inside the box after ONE minute?

A. increases
B. decreases
C. no change