Which of the following is correct for CD8 T cells?

• A. CD8 T cells only recognize virus-infected cells
• B. CD8 T cell receptor recognizes epitopes that are also commonly recognized by B cells
• C. In the thymus, CD8 T cells undergo positive selection only, whereas CD4 T cells undergo negative selection only
• D. CD8 T cells can kill individual virus-infected cells in a contact dependent fashion