The correct answer is B. The surrounding air was greater than 10 degrees Celsius.
In order for the water to increase in temperature, there would have to be a heat energy exchange with a substance having a higher temperature. The glass of water takes in heat energy (endothermic) from the air surrounding it until reaching an equal temperature or equilibrium. Because of the existence of this balance, C and D are ruled out because the final temperature would be even. Otherwise, the transfer would still be occurring and that wouldn’t be the “final” temperature.
Attached is a visual representation if that makes it clearer.
