Which statement describes the transfer of heat energy that occurs when an ice cube is added to an insulated container with 100 milliliters of
water at 25°c?
(1) both the ice cube and the water lose heat energy.
(2) both the ice cube and the water gain heat energy.
(3) the ice cube gains heat energy and the water loses heat energy.
(4) the ice cube loses heat energy and the water gains heat energy.

The answer to this question would be: (3) The ice cube gains heat energy and the water loses heat energy.

Based on the law of conservation of energy, the energy in an isolated system should be constant. If something receives energy, other must be losing energy. The option 1 and 2  definitely false because the total energy is not constant.
In this case, the ice should have lower heat energy, so the ice should be the one who receives energy from the water