Answer:
Option (A).
Explanation:
Infection may be defined as the invasion of pathogens into the body's tissue of the organism. Various organisms like bacteria, fungi, virus and plasmodim can acts as a pathogen for the organism.
The secondary infection may be defined as the infection that occurs after the treatment of the previous infection. This infection may occur due to the changes in the immune system or by the treatment of the previous infection.
Thus, the correct answer is option (A).