This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
Which of the following antibiotic acts by inhibition of cytoplasmic membrane function? 
Select and explain. 
A. Penicillin, B. Polymycin, C. Streptomycin, D. Novobiocin
B: Polymycin
Answer: B: Polymycin 
Explanation: Polymyxin bacitracin acts by inhibiting cell membrane or plasma membrane Not cell wall Penicillin -cell wall,streptomycin-protein synthesis inhibition Ref: CP Baveja 4th ed Pg:625