The right option is Capsid
A capsid is a protein coat that
encloses the nucleic acid (RNA, DNA etc.) of a virus particle. Capsids are in different
shapes and the common ones are icosahedral, prolate, and helical. The main role
of the capsid is to protect the virus by ensuring that the nucleic acid inside
of it is safe.
Erosion and collisions
such as mountain ranges and conyons
B is the correct answer to your question