One mole of an ideal gas in initial state A undergoes a cyclic process ABCA, as shown in the figure. Its pressure at A is `P_0`. Choose the correct option (s) from the following
A. Internal energies at A and B are the same
B. work done by the gas in process AB is `P_(0)V_(0) ln 4`
C. pressure at C is `(P_(O))/4`
D. Temperature at C is `(T_(O))/4`