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 58 year old woman, who had backache and recurrent chest infections for 6 months, develops sudden. weakness of the legs and urinary retention. Her investigations show a hemoglobin of 7.3 gm/ dl, serum calcium 12.6 mg/dl, phosphate-2.5 mg/ dl, alkaline phosphatase-100u/I, serum albumin-3 gm/dl, globulin - 7.1 gin/dl and urea - 178 mg/d.What is the most likely diagnosis - 
Select and explain. 
A. Lung cancer, B. Disseminated tuberculosis, C. Multiple myeloma, D. Osteoporosis
C: Multiple myeloma
Answer: C: Multiple myeloma 
Explanation: None