Why Must T Cell Activation Take Place Outside the Thymus

Multiple Choice

Why must T cell activation take place outside the thymus?

A) An activated T cell could destroy the other maturing T cells.
B) An activated T cell could then destroy the thymus gland itself.
C) Many T cells are self-reactive and must be eliminated in the thymus before any possibility of activation.
D) Other cell types might be accidentally activated in the thymus.