How can someone be added to a list in Marketo?

The correct answer highlights the primary methods by which individuals can be added to a list in Marketo. Specifically, the process involves either importing lists directly into Marketo or using specific flow steps within a campaign.

When a list is imported, it typically comes from an external source, such as a CSV file, where user data has been pre-collected. This allows for a bulk addition of contacts into the system. Alternatively, using flow steps allows marketers to dynamically add individuals to lists based on various criteria or actions they take—such as filling out a form or meeting specific engagement thresholds.

The other choices do not accurately represent the mechanisms by which contacts are systematically added to lists in Marketo. Directly emailing a person does not enroll them in a list, forms are typically gateways for capturing leads rather than solely mechanisms for list addition, and while inviting individuals to events can lead to engagement, it does not inherently add them to a specific marketing list unless another action occurs within Marketo to facilitate that. Thus, utilizing list imports or specific flow steps encompasses the appropriate functions available to users for managing their lists effectively within the Marketo platform.