When Producing Monoclonal Antibodies,why Is It Important to Use as a Fusion

When producing monoclonal antibodies,why is it important to use as a fusion partner a myeloma cell that is unable to produce its own immunoglobulin?

A) to ensure that allelic exclusion of μ chain occurs normally
B) to ensure that the antibodies are homogeneous and able to make strong bivalent attachments to multivalent antigens
C) to ensure that the monoclonal antibodies are not autoreactive
D) to provide a greater opportunity for making a successful rearrangement at the light-chain locus
E) to ensure that antibodies are secreted and not membrane-bound.