Answer:
The correct answer is - Haemophilus influenzae serotype b .
Step-by-step explanation:
Meningitis is a medical condition that is characterized by the inflammation of the protective membrane of the spinal cord or spine and brain in an individual. Commonly it is caused by the infection by the bacteria or viruses that cause the swelling to the protective membrane of the spine and brain.
In this case, it is mention that the cause of the meningitis is due to the gram-negative rods that means it is a bacterial infection and HiB or Haemophilus influenzae serotype b that cause invasive disease in most commonly in kids below the age of 5 such as meningitis and pneumonia.
Thus, the correct answer is - Haemophilus influenzae serotype b .