It is C because a nation is a group of culturally similar people, for example, the Greeks, who all followed the same religion. For states, think of the United States of America. The states are separate areas within the country and each can have slightly different laws while following the outline made by Congress.
three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries. A divergent boundary occurs when two tectonic plates move away from each other.