Anh measured the temperature of a pond near his house. Before he left for school, the water in the pond was 18 degrees celsius. When he came home from school, the temperature of the pond was higher than it was in the morning. What happened to the water molecules while he was at school?

A) The molecules get closer together.
B) the molecules started moving faster.
C) The water lost its molecules.
D) The molecules became larger.