# In an example of “call options”

The following is an excerpt from Introduction to the Mathematics of Finance by Roman:

As a more concrete example, suppose that IBM is selling for $\$100$per share at this moment. A$3$month call option on IBM with strike price$\$102$ is a contract between the buyer and the seller of the option that says that the buyer may (but is not required to) purchase $\color{blue}{\bf 100}$ shares of IBM from the seller for $\$102$per share at any time during the next$3$months. In this example is the number$\color{blue}{100}\$ in blue arbitrarily picked by the author? Is it relevant to the concept of "call option"?