Which one of the combinations of the following statements is true about antibody structure?

Q. Which one of the combinations of the following statements is true about antibody structure?

P. Limited proteolysis of rabbit IgG with the enzyme pepsin generates two antigen-binding regions (Fab) and an Fc fragment

Q. Limited proteolysis of rabbit IgG with the enzyme papain generates a single bivalent antigen-binding region F(ab¢)2 and peptide fragments

R. The Fc fragment of IgG can self-associate and crystallize into a lattice

S. The F(ab¢)2 fragment of IgG is composed of both light and heavy chains

(A) P and Q only                      

(B) P and R only

(C) R and S only                       

(D) Q and S only

Ans: R and S only