A 62-year-old man with a 10-year history of rheumatoid arthritis presents with nephrotic syndrome (proteinuria 8 g/day, serum albumin 2.1 g/dL). Renal biopsy shows deposits that stain positive with Congo red and display the characteristic finding marked **D** in the diagram under polarized light microscopy. Which of the following is the most likely type of amyloidosis in this patient?