Adiabatic Processes and Ideal Gases

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason(R).         
Assertion (A) : In an insulated container, a gas is adiabatically shrunk to half of its initial volume. The temperature of the gas decreases.         
Reason (R) : Free expansion of an ideal gas is an irreversible and an adiabatic process.          
In the light of the above statement, choose the correct answer from the options given below :