Answer: The correct answer is- A) decreased antibody production.
Compromised immune system means that the ability of an individual to fight the infectious diseases has been diminished. In other words, when the immunity is declined it is termed as compromised immune system.
This can be caused by various factors such as medical conditions like heart disease, poor sanitary conditions, lung disease, blood disorders, malnutrition.
Due to decrease in the immunity of the individual, production of antibodies ( protein molecules that help in clearing pathogens like bacteria and virus) is decreased.