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: Microbiology
Normal ratio of CD4 (T4) : CD8 (T8) is 
Select and explain. 
A. 2:01, B. 1:02, C. 3:01, D. 1:03
A: 2:01
Answer: A: 2:01 
Explanation: Both CD4+ and CD8+ T cells contain several subsets. The CD4+/CD8+ ratio in the peripheral blood of healthy adults and mice is about 2:1, and an altered ratio can indicate diseases relating to immunodeficiency or autoimmunity. An inverted CD4+/CD8+ ratio indicates an impaired immune system. 
Ref :https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5667733