The Diagram on the Left in Box a Shows the Interface

Multiple Choice

The diagram on the left in box A shows the interface of solid and liquid phases of a single substance where each sphere represents a molecule of that substance. Which box, A, B, or C best represents what the molecules of this substance would look like if heat were added? Which box best represents what the molecules of this substance would look like if heat were taken away?

A) A and C
B) B and C
C) A and B
D) C and B