In an Isothermal Process, the Pressure on 1 Mol of an Ideal

In an isothermal process, the pressure on 1 mol of an ideal monatomic gas suddenly changes from 4.00 atm to 100.0 atm at 25°C.
-Calculate $\Delta$ T.

A) 25°C
B) 100°C
C) 0°C
D) 48°C
E) none of these