Context: Two identical aquariums were next to an open window. One aquarium had a plastic cover on it, and the other was uncovered. This table shows how the temperature of each aquarium changed over 1.5hours.
During this time, thermal energy was transferred from () to ().
A. each aquarium . . . the surroundings
B. the surroundings . . . each aquarium
From the given choices, choose the correct answer and respond with the letter of that choice.

A