Which classes of antibodies is most likely to be made by the oldest plasma cell in a population of b cells?

Options are not provided in teh question. The complete question is as following:

Which of the following classes of antibodies is most likely to be made by the oldest plasma cell in a population of B cells?

a. IgM

b. IgG

c. IgA

d. None of the listed responses is correct.

c. IgA

Explanation:

Specialized white blood cells called B lymphocytes (or B cells) contain antibodies. The mature B cells, or plasma cells, secrete millions of antibodies into the lymphatic system and the bloodstream. The plasma cell antibodies have the exact same antigen-binding site and specificity as the precursors to their B cells. Five different types of antibodies are present in humans: IgA, IgM, IgG, IgD,IgE.

In the oldest plasma cell igA classes of antobodies are present because initially plasma cells secret IgM but it switch and forms IgG, as the plasm aget older ans switch of antibodies takes place for scond time they can make IgA or IgE.

Hence, the correct option is c. IgA.