In addition to the physical exam and functional assessment, which of the following is used to assess response to treatment for rheumatoid arthritis?

Choice A reason: White blood cell counts may be affected by infection or medications but are not reliable markers for RA activity. Choice B reason: Erythrocyte sedimentation rate (ESR) is an inflammatory marker commonly used to monitor disease activity and response to treatment in rheumatoid arthritis. Choice C reason: Hemoglobin levels may decrease due to chronic disease or medications but do not directly measure RA activity. Choice D reason: Absolute neutrophil counts are used to monitor for medication-induced cytopenias, not RA disease activity.