This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following penicillins has the best gram negative spectrum? 
Select and explain. 
A. Methicillin, B. Ampicillin, C. Penicillin V, D. Cefixime
B: Ampicillin
Answer: B: Ampicillin 
Explanation: None