8. Which of the following statements about glycogen metabolism is correct? 1. Glycogen is mainly found in liver and muscle. 2. The average chain length of the branches in glycogen is 25 glucose residues. 3. Glycogen phosphorylase cleaves the a(1→6) bonds in glycogen. 4. Glycogen phosphorylase responds differently to allosteric effectors in its phosphorylated and dephosphorylated forms. (A) 1, 2 and 3 are correct. (B) 1, 3 and 4 are correct. (C) 2 and 3 are correct. (D) 1 and 4 are correct. (E) All are correct.