A two yrs old child is brought to the emergency with history of fever and vomiting.On examination he has neck rigidity.The CSF examination shows polymorphs more that 2000/meu l protein 100 mg/dl and glucose 10 mg/dl.The gram stain shows the presence of Gram negative coccobacilli.The culture shows growth of bacteria only on chocolate agar and not on blood agar.The causative agent is

• A. Neisseria meningitides
• B. Haemophilus influenzae
• C. Branhamella catarrhalis
• D. Legionella pneumophila