This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders), Subject name: Microbiology
Common between B and T cells - (PGI Nov 14) 
Select and explain. 
A. Origin from same cell lineage, B. Site differentiation, C. Antigenic mark, D. Both humoral and cellular immunity
A: Origin from same cell lineage
Answer: A: Origin from same cell lineage 
Explanation: 1. Both T and B cells originate from same cell lineage - Lymphoid lineage 2. But, differentiation occurs at different sites-T-cell in Thymus & B-cell in Bone marrow.