Prativa Rathor, 80yrs, asymptomatic was detected to have a monoclonal spike on serum electrophoresis (IgG levels 1.5g/dl).Bone marrow revealed plasma cells of 8%.The most likely diagnosis is:

• A. Indolent myeloma
• B. Multiple myeloma
• C. Waldenstorm's macroglobulinemia
• D. Monoclonal gammopathy of unknown significance