One mole of a monatomic ideal gas undergoes a cyclic process as shown in the figure (where V is the volume and T is the temperature). Which of the statements below is (are) true?

A)Process-I is not isochoric,V is decreasing .B)Process-II is isothermal expansion     ΔU=0,  W>0   ΔQ>0    C)Process-IV is isothermal compression ,ΔU=0,W<0  ΔQ<0D)Process-I and III are NOT isobaric because in isobaric process T∝V hence isobaric T-V graph will be linear.