You recently sold $100$ shares of Facebook stock to your uncle. You had the certificates and gave them to him. In exchange, he wrote you a check. Which of the following best describes this transaction?

a$.$ This is an example of a money market transaction.

b$.$ This is an example of a primary market transaction.

c$.$ This is an example of an exchange of physical assets.

d$.$ This is an example of a direct transfer of capital.

e$.$ This is an example of a derivative market transaction