This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Anti-HIV drug combination that should not be used 
Select and explain. 
A. Zidovudine + Stavudine, B. Atazanavir + Indinavir., C. Didanosine/stavudine + Zalcitabine, D. All of the above.
D: All of the above.
Answer: D: All of the above. 
Explanation: Anti-HIV drug combinations that should NOT be used are:

Zidovudine + Stavudine: Pharmacological antagonism (compete for intracellular phosphorylation)
Atazanavir + Indinavir: Additive unconjugated hyperbilirubinemia.
Didanosine/stavudine + Zalcitabine: Additive peripheral neuropathy.
Lamivudine + Zalcitabine: In vitro antagonism.