Which shape is used to send a work object through another flow(spawns multiple parallel flows) based on information in the pages of a Page List or Page Group property.

The 'Split for each' shape is specifically designed to spawn multiple parallel flows by iterating through a Page List or Page Group property, creating a separate flow execution for each page. 'Spin off' creates a single child flow, 'Split join' waits for all branches to complete before proceeding, and 'Called flow' invokes another flow as a subprocess.