The correct answer is D. The air will be warmer than the water.
Water has a higher specific heat capacity compared to air, meaning it takes longer for water to heat up or cool down compared to air. When left out overnight, the water in the cup will lose heat to its surroundings (the cooler room air), causing it to gradually reach a temperature closer to that of the surrounding air. Therefore, in the morning, the air in the room is likely to be warmer than the water in the cup.
