フリー問題

問題文

An application contains a flow that has no event source at all. How can that flow be executed?

選択肢

1. Another flow must call it with a Flow Reference, since without a source there is nothing that can trigger it from the outside.
2. It can be invoked from outside over HTTP by using the flow name as the request path, and the runtime exposes every flow in the application that way.
3. It is executed whenever any other flow in the same application finishes, because flows without a source act as completion handlers for the application and run in the order in which they appear in the configuration file.
4. The runtime executes it once at deployment time.