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
An elderly male presents with headache, recurrent infections and multiple punched out lytic lesions of x-ray skull. Which of the following investigation will best help in establishing the diagnosis? 
Select and explain. 
A. Serum calcium, B. Protein Electrophoresis, C. Acid phosphatase levels, D. Alkaline phosphatase levels
B: Protein Electrophoresis
Answer: B: Protein Electrophoresis 
Explanation: Patients presenting with symptoms such as headache, recurrent infections and multiple punched out lytic lesion on the skull suggest a diagnosis of Multiple Myeloma. It can be diagnosed by performing protein electrophoresis which shows a characteristic monoclonal spike visible in the beta or gamma globulin region. Ref: Current Medical Diagnosis and Treatment, 2012, Chapter 13