Final answer:
The college-aged student with influenza is most infectious during the prodromal stage of the infection.
Step-by-step explanation:
The college-aged student with influenza is most infectious during the prodromal stage of the infection. It is during this phase that the pathogen continues to multiply in the host and general signs and symptoms of illness become observable. This is also when the immune system is activated, leading to fever, pain, soreness, swelling, or inflammation.