The diagram illustrates a section of the immune response. What are P, Q and R?
- AP: antibody, Q: B-lymphocyte, R: T helper cell
- BP: antibody, Q: T helper cell, R: B-lymphocyte
- CP: antigen, Q: B-lymphocyte, R: T helper cell
- DP: antigen, Q: T helper cell, R: B-lymphocyte