To automatically register prospects to a webinar upon form submission, adding a completion action to register prospects on the form is the most efficient and straightforward automation tool to use. Completion actions are directly related to form submissions and can immediately trigger subsequent activities such as registering for an event. This option ensures that the registration process is automated right after each submission without requiring additional steps or rules.

The correct answer is Lookup. Lookup fields in Salesforce are not supported for syncing with Pardot because they are used to relate records between different objects and do not hold values that can be directly synced.

For a newly created lead record in Salesforce to be created in Pardot immediately, the lead record must have an email address at the time of creation and the Salesforce connector must be set to automatically create prospects. The email address is essential because it uniquely identifies the prospect, while the connector setting ensures that new leads are automatically synchronized into Pardot.

The two components of a dynamic list are: it automatically updates list membership based on criteria and it can add an action that triggers when a new prospect is added. Dynamic lists are designed to update themselves in real-time based on the criteria set, ensuring that the list remains current with no manual updates needed. Additionally, they can include automated actions to be performed when new members meet the criteria to be added to the list. Splitting a dynamic list into static lists does not constitute a component of the dynamic list itself but is rather a potential action that can be performed on it.