The true statements are all of the above. Hence, option D is correct.
A Mucous membrane may be defined as the epithelial tissues that involve the inner lining of the internal organs that secrete mucus. It includes the respiratory system, gut, etc.
Mucous membranes line cavities that have an external opening in the body. Serous membranes line internal cavities that have no external opening in the body, while a visceral membrane is a type of membrane that is attached to an organ.
Therefore, the correct option for this question is D, i.e. all the above.
To learn more about the Mucosal membrane, refer to the link:
https://brainly.com/question/26922615
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