||A 48 year old man with AIDS comes to clinic for a regular follow-up. He was recently started on zidovudine (AZT or ZDV), lamivudine, and nelfinavir. He was previously seen by a different doctor in the clinic. The patient states that his viral load is now undetectable. His white count is 1,200/mm3 with 75% neutrophils. Six months ago, his viral load was 65,000, and his white cell count was 7,500/mm3 with 65% neutrophils. What is the most appropriate action at this time?
A. Switch lamivudine to didanosine
B. Switch nelfinavir to efavirenz
C. Start colony-stimulating factor
D. Bone-marrow biopsy
E. Switch the zidovudine (AZT) to stavudine