Normal ratio of CD4 (T4) : CD8 (T8) is: (A) 2:01, (B) 1:02, (C) 3:01, (D) 1:03
Answer is A. 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