This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
A 27-year-old woman presents with a red rash over her cheeks, and pain and swelling in both knees as well as several small joints in her hands. She notes that the rash is worse with sun exposure. Medical evaluation reveals oral ulceration, positive ANA, and 3+ proteinuria. Which of the following is the most likely mechanism for the renal damage in this condition? 
Select and explain. 
A. vasculitis, B. micro-emboli, C. anti-basement membrane antibodies, D. deposition of circulating immune complexes
D: deposition of circulating immune complexes
Answer: D: deposition of circulating immune complexes 
Explanation: Renal disease is usually secondary to deposition of circulating immune complex. Although most patients with SLE have such deposits, only half have clinical nephritis as defined by proteinuria. Renal biopsy can provide both prognostic and therapeutic information.