Which of the following are most abundant types of antibodies?

The correct option is A IgG

A. IgA represents 15-20% of the serum immunoglobins and is the second most abundant Ig.

B. IgE is found on the surface membrane of basophils and mast cells.

C. IgA is the most abundant Ig in serum and constitutes about 80% of the total Igs.

D. IgM is the largest Ig and constitutes about 5-10% of the total Igs.

So, the correct answer is 'IgG'.