Answer:
A. Mucous membrane.
Explanation:
Mucous secrete mucus. When any pathogen tries to enter into the human body, the mucous snares those pathogens and prevents them from entering into the human body. As an example: Nasal hairs help to remove or fight against suspended micro-organisms when they are present in the air and try to enter into the nose. Cilia is a small type of hairs that beat to force mucous to the pharynx for swallowing into the stomach.
