[A] : Lymphocytes arise from bone marrow and present in the blood, lymph and connec- tive tissues.
[R]: Lymphocytes migrate to thymus. where they develop into T cells and begin to mature.
A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false