__________________ are licensed to rescue germinal center B cells & induce ________ or __________________. 
Group of answer choices 
a. Follicular helper T cells; class switching; somatic hypermutation 
b. Immature T cells; class switching; somatic hypermutation 
c. Follicular helper T cells; apoptosis; class switching 
d. Immature T cells; somatic hypermutation; apoptosis.