One mole of diatomic ideal gas undergoes a cyclic process ABC as shown in figure. The process BC is adiabatic. The temperatures at A, B and C are 400 K, 800 K and 600 K respectively. Choose the correct statement:

A

The change in internal energy in whole cyclic process is 250 R

B

The change in internal energy in the process CA is 700 R

C

The change in internal energy in the process AB is -350 R

D

The change in internal energy in the process BC is -500 R