Answer:
Option-A
Step-by-step explanation:
β-Lactam antibiotics are the antibiotics that contain β-Lactam rings in their structures like in cephalosporins and penicillin.
The antibiotics act by inhibiting or disrupting the process of cell wall formation in the bacteria which is mediated by an enzyme called penicillin-binding proteins.
To bind covalently to the PBP proteins, the antibiotic has to diffuse through the bacterial cell wall. since the gram-negative bacteria contain an additional lipopolysaccharide layer which decreases the penetration of the antibiotic, therefore, the gram-positive bacteria lacking the additional layer are more susceptible than gram-negative bacteria.
Thus, option-A is the correct answer.