This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
A diagnosed case of SLE has renal biopsy finding suggestive of mesangial proliferative nephropathy. It belong to which class of lupus nephritis: 
Select and explain. 
A. Class I, B. Class II, C. Class III, D. Class IV
B: Class II
Answer: B: Class II 
Explanation: Classification of lupus nephritis: Class I - Minimal mesangial lupus nephritis Class II - Mesangial proliferative lupus nephritis Class III - Focal lupus nephritis Class IV - Diffuse lupus nephritis CLass V - Membranous lupus nephritis Class VI - Advanced sclerotic lupus nephritis Ref: Harrison Edition - 18, Page - 2727