A 74-year-old Caucasian woman presents for a routine physical and is found to be anemic. Her colonoscopy a year ago was normal, and additional laboratory tests confirm that she is not iron deficient....

A 74-year-old Caucasian woman presents for a routine physical and is found to be anemic. Her colonoscopy a year ago was normal, and additional laboratory tests confirm that she is not iron deficient. Serum protein electrophoresis demonstrates a protein spike, and her kidney biopsy microscopically demonstrates a translucent, smooth, glassy material. Multiple myeloma is diagnosed. What is the etiology of her amyloidosis?

A. Hereditary amyloidosis

B. Misfolded mutant proteins

C. Reactive systemic amyloidosis

D. Light chain amyloidosis