For a classroom demonstration, a chemistry teacher puts samples of two different pure solid powders in a beaker. The teacher places the beaker on a small wooden board with a wet surface, then stirs the contents of the beaker. After a short time the students observe that the bottom of the beaker is frozen to the wood surface. The teacher ask the students to make a claim about the observation and justify their claims. Which of the following is the best claim and justification based on the students obseration?

A) an exothermic chemical change occured because hea flowed from the contents of the beaker to the room.

B) An exothermic physical change occured because the heat flowed from the contents of the beaker and the water on the board to the room.

C) An endothermic physical change occured because the freezing of water is an endothermic process.

D) An endothermic chemical change occured because the temperature of the beaker and the water on the board decreased as heat was absorbed by the reaction.