This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hemodynamics, Subject name: Pathology
Which is the most common defectively produced antibody in multiple myeloma? 
Select and explain. 
A. Ig G, B. Ig M, C. Ig A, D. Ig D
A: Ig G
Answer: A: Ig G 
Explanation: Ref: Robbin's Pathology, 9th ed. pg. 598-99* The over production of light chains of IgG is the most common abnormality in multiple myeloma. In Waldenstrom cryoglobulinemia, IgM is overproduced.* Most common presentation of multiple myeloma is anemia >bone pain.* Least common presentation of multiple myeloma is hyperviscosity* Investigation of choice for multiple myeloma is bone marrow biopsy* Screening test for multiple myeloma is serum electrophoresis showing M spike* Most common cause of death in multiple myeloma is infections* Most common cause of kidney damage in multiple myeloma is hypercalcemia.