Answer:
B
Step-by-step explanation:
A is not the answer. Although the statement is accurate in regards to gases, it does not explain why liquids and gases can flow.
B is the answer. Solids are in fixed structures. When you apply heat or pressure, these structures are broken apart and allowed to move freely.
C is not the answer. This is inaccurate. Changing the phase of a substance does not change the size of the particle.
D is not the answer. The opposite of this statement is true. The attractive forces between particles in a solid allow the substance to hold its structure. When you apply heat or pressure, the attractive forces are overpowered and the structure is broken.