Temperature versus pressure graph of an ideal gas is shown in the figure. During the process AB,

(A) pressure is inversely proportional to volume (B) work done by the atmosphere on the gas is positive (C) internal energy depends on the direction from A to B or from B to A (D) both (A) and (B)

Since the process is isothermal, PV = constant.
Therefore, pressure is inversely proportional to volume.
Since the pressure increases from A to B, volume decreases. Therefore, work is done on the gas.
Internal energy is constant for the above process.
Therefore the correct answer is both (A) and (B)