Explanation
According to the Salesforce documentation, the automation tool that should be used to solve the need of recreating a lead from a prospect that was marked as [[crm_deleted]] in Marketing Cloud Account Engagement is engagement studio. Engagement studio is a feature that allows users to build, test, and report on automated programs that send targeted emails and perform actions based on prospect behavior and criteria.
Engagement studio can be used to create a program that triggers when a prospect submits the Request a Demo form, checks if the prospect is marked as [[crm_deleted]], and recreates the prospect as a lead in Salesforce.
Segmentation rule, automation rule, and dynamic list are not automation tools that can be used to solve the need of recreating a lead from a prospect that was marked as [[crm_deleted]] in Marketing Cloud Account Engagement, as they are related to other aspects of automation, such as segmenting, updating, and listing prospects, but not recreating leads. References: Salesforce documentation