The correct option is C Cell wall
The antibiotics are the chemical substances produced by the natural metabolic processes of bacteria and fungi as their natural defense against other microorganisms. Penicillin is an antibiotic that target the peptide cross-links in the peptidoglycan and disrupt the cell wall integrity. Exposure of penicillin to bacteria stops the cell wall synthesis by inhibition of formation of peptide linkage and bacteria become protoplast (a fragile cell bounded only by a membrane) which is highly susceptible to lysis. Thus, the correct answer is option C.