Question: A 5-year-old boy with symptoms of possible meningitis is seen in an emergency department. Gram-negative diplococci and abundant polymorphonuclear leukocytes are observed in the Gram stain of the cerebrospinal fluid sediment. What microorganism does it suggest as a possible cause of the infection ?: 
 Options:  <1> Haemophilus influenzae. <2> Streptococcus pneumoniae <3> Streptococcus agalactiae. <4> Neisseria meningitidis. <5> Listeria monocytogenes.
4