ThreatPlaybook uses the playbook apply feature command to push user-story--driven threat models to the server. The -f flag specifies the path to the YAML file containing the defined user stories, abuser stories, and threat scenarios, while the -p flag specifies the target project. Option C correctly combines these parameters. The -y flag is invalid in this context, and options that misuse -t instead of -p do not correctly identify the project destination. Executing this command during the Plan stage enables teams to integrate threat modeling early, ensuring security risks are identified and addressed before development and deployment proceed.