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
Gram-negative cocci is 
Select and explain. 
A. Nisseria, B. Helicobactor, C. Cholera, D. Campylobactor
A: Nisseria
Answer: A: Nisseria 
Explanation: Neisseria is a gram-negative coccus typically arranged in pairs. Vibrio cholerae are gram-negative, curved bacilli. Campylobacter is gram-negative rods, typically comma-shaped. Helicobacter is a gram-negative spiral rod. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 230