contestada

All of these sentences are from the same paragraph. Which is the topic
sentence?
O A. There are three states of matter: solid, liquid, and gas.
B. In a liquid state, the particles in matter lie together but move
around one another randomly.
C. Gas particles do not lie close to one another but move about
randomly in the container in which they reside.
O D. Solid matter does not necessarily conform to the shape of the
container it resides in.