Which of the following is a viral infection that most adults contract 2 to 4 times a year?

a. bacterial pneumonia

b. strep throat

c. influenza

d. the common cold

The common cold, just took the test.

The viral infection that most adults contract 2 to 4 times a year is D. the common cold. It is a common illness that manifests as coughing, sneezing, or sometimes temperature, but it is nothing serious. On the other hand, bacterial pneumonia, step throat, and influenza are far more serious illnesses that need to be treated immediately.