McArdle's disease causes muscle cramps and muscle fatigue with increased muscle glycogen. Which of the following enzymes is deficient?

Muscle Phosphorylase deficiency leads to a glycogen storage disease and , in young adults, an inability to do strenuous physical work because of muscular cramps resulting from ischemia. The compromised phosphorylation of muscle glycogen characteristic of McArdle's disease compels the muscles to rely on auxiliary energy sources such as free fatty acid and ambient glucose. regarding glycogen storage disease (GSD) GSD type Disease name Enzyme defeciency GSD 1 Von gierke's Glucose 6 phosphatase GSD 2 Pompe's Acid Maltase GSD 3 Cori's / Forbe's Glycogen debrancher GSD 4 Anderson's Glycogen branching enzyme GSD 5 Mc Ardle Muscle glycogen phosphorylase GSD 6 Her's Liver glycogen phosphorylase GSD 7 Tauri's Muscle phosphofructokinase