How Were the Cells Responsible for Cell- Mediated Immunity First

How were the cells responsible for cell- mediated immunity first identified as T lymphocytes?

A) Metchnikoff demonstrated phagocytosis of fungal spores by Daphnia blood cells.
B) Ehrlich demonstrated it using cells isolated from the Bursa of Fabricius in chickens.
C) Glick demonstrated it using cells isolated from chicken thymus.
D) Landsteiner demonstrated it showing incompatibility between sera of people with different blood groups.