A 17-Year-Old Male Presents to the Emergency Room Lethargic with a Fever

A 17-year-old male presents to the emergency room lethargic with a fever and rash. Blood cultures and cerebrospinal fluid samples are taken. The direct Gram stain of the CSF is provided.
Source: CDC and Susan Lindsley
At 24 hours, the blood cultures and CSF culture grow the same organism. Testing
Results include:
Gram stain: same as the direct smear
Oxidase: purple
Glucose and maltose fermentation tubes: yellow
Lactose and sucrose fermentation tubes: red
Butyrate esterase: no color change
After a thorough history was taken with the assistance of the parents, it was
Discovered the patient has had two similar disease episodes in the past two years with
The same organism. The physician should test the patient for

A) a deficiency of the classical pathway of the complement system.
B) a deficiency of the common terminal pathway of the complement system.
C) common variable immune deficiency.
D) severe combined immunodeficiency.