The correct option is (a) True
To explain I would say: Lysozyme catalyzes the β (1 → 4) glycosidic linkages of NAM (N-acetyl muramic acid) and NAG (N-acetyl glucosamine) present in bacterial peptidoglycan. Peptidoglycan content in high in gram positive bacteria as compared to gram negative bacteria. Hence gram positive bacteria are highly susceptible lysozyme treatment.