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: Medicine
Pneumococcal vaccination is indicated in   a) Postsplenectomy  b) Sickle cell anemia  c) HIV  d) After radiotherapy 
Select and explain. 
A. abc, B. abd, C. ac, D. acd
A: abc
Answer: A: abc 
Explanation: None