Answer:
c.They are leftover planetesimals from the inner part of solar system.
Explanation:
Asteroids are the objects which are small in size and made up of rocky material and they revolve around the Sun. The size of these asteroids are smaller than the planets.
There are the most asteroids which are lies in the asteroid belt.
Asteroids were formed when our solar system began of about 4.6 Billion years ago when a collapse of big cloud and dust happened and they are the the left over parts of our solar system