best next step! - usmleemedd2013

[ArchivalUser]

65 yo male comes to ed due to generalized weakness , fatigue .he has been smoking for about 20 years ,one pack a day.He also complains of severe back pain ,he just remmember having left rib pain in the past.Physical exam:pallor and hepatomegaly.labs:hypercalcemia.Bun 80 and creatinine:2
what is the best next step in mgt???
A-bone marrow biopsy
B- xray
C-serum inmunoelectrophoresis
D-bone biopsy
E-ANA