This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'All are used against anaerobic streptococci except \nSelect and explain. \nA. Penicillin, B. Carbenicillin, C. Clindamycin, D. Vancomycin', 'role': 'user'}, {'content': "Answer: B \nExplanation: Penicillin, clindamycin and metronidazole are the most active drugs against anaerobes. Carbenicillin is a bactericidal antibiotic belonging to the carboxypenicillin subgroup of the penicillins.It has Gram-negative coverage which includes Pseudomonas aeruginosa but limited Gram-positive coverage. Streptococci are Gram-positive. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Pg:277", 'role': 'assistant'}]