The correct option is C Oort Cloud
The Oort Cloud, named after the Dutch astronomer, Jan Oort, is a cloud of predominantly icy celestial objects and rocks floating around on the edge of the solar system, light years away from the Sun. It was first proposed in 1907. However, we are yet to prove its existence by a space mission. The Oort Cloud acts as a storage for all the comets that we occasionally observe in the sky.