Final answer:
Ashby's Law of Requisite Variety relates to the ability of a control system to handle variety in the system it manages, and b) The content of the spam email messages is an example of this law in spam emails since spam filters must adapt to the varying content of spam.
Step-by-step explanation:
Ashby's Law of Requisite Variety states that in order to effectively manage a system, the control mechanism must have a level of complexity (variety) that is equal to or greater than the system it is trying to control. When applied to spam emails, this concept can pertain to the measures that an email system takes to filter and prevent spam. The correct answer to the provided question about an example of Ashby's Law of Requisite Variety in spam emails is b) The content of the spam email messages.
The content of spam emails can vary greatly to adapt to spam filters, and in response, spam filters must evolve to handle a wide variety of spam content. The variety in the spam emails' content requires an equal level of variety in spam detection techniques to effectively manage the incoming spam. Other options such as the volume, sender's name, and frequency are aspects of spam but do not directly exemplify Ashby's Law which is more about the adaptation and response mechanisms to the variety in the system.