This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
An elederly male presented with headache, fever and hemiparasis of right side. On fuher examination and investigation a diagnosis of brain abscess was made. Which of the following antibacterial/ antibacterials is effective in this patient 
Select and explain. 
A. Gentamycin, B. Doxycycline, C. Streptomycin, D. A combination of Cephalosporin and Metronidazole
D: A combination of Cephalosporin and Metronidazole
Answer: D: A combination of Cephalosporin and Metronidazole 
Explanation: A 6-week combination of third-generation cephalosporin and metronidazole cures most cases of community-acquired brain abscess in immunocompetent patients. Coverage for streptococci can be attained by a high dose of penicillin G or a third-generation cephalosporin (eg, cefotaxime, ceftriaxone Ref Harrison20th edition pg 2234