The antibodies found in mucus, saliva, and tears are:

• A. IgM
• B. IgE
• C. IgA
• D. IgG

Answer: (C)

Verified step by step guidance

1. Understand that antibodies, also known as immunoglobulins, are proteins produced by B cells that help the immune system identify and neutralize pathogens like bacteria and viruses.
2. Recall that different classes of antibodies (IgA, IgG, IgM, IgE, IgD) have distinct roles and locations in the body.
3. Focus on the antibody class that is primarily found in mucosal areas such as mucus membranes, saliva, and tears, which are key sites for the first line of defense against pathogens.
4. Identify that IgA is the antibody class specialized for mucosal immunity, providing protection by preventing pathogen adherence and invasion at these surfaces.
5. Conclude that the antibodies found in mucus, saliva, and tears are IgA, distinguishing it from other antibody classes like IgM, IgE, and IgG that have different primary functions and locations.