Suppose That You Had a Cold Last Month, and You

Suppose that you had a cold last month, and you caught another one this month from your brother. Which of the following explains why you caught a new cold?

A) Your antigen-presenting cells did not recognize the second cold virus.
B) The two cold viruses are significantly different.
C) Memory cells were not formed as a response to the first cold.
D) The antibodies formed as a response to the first cold were degraded.