Multiple myeloma is an neoplastic proliferation of plasma cells, and since plasma cells don’t have surface Ig bound innately, that was the only “true” option.
@infundibidum6 So, I got to bleomycin due to SketchyMicro. Bleomycin can cause hyperpigmentation and pulmonary fibrosis, and I didn’t have any connections to chlorambucil. Anthracyclines can be used for all sorts of malignancies (free radicals kill lots of stuff), so the exact indications did less for me to get to the answer than it might have with another category. n=1, but it’s not a magic memorization answer at least.