A: A Flow can guide sales reps through a set of scripted steps and call an Apex action to interact with an external REST endpoint.
B: An Invocable method is used to make an Apex method callable from a Flow. This method can call the REST endpoint and return the data for display.
Why not other options?
C: Future methods are asynchronous and cannot return data to the user in real time.
D: Triggers are used for database events, not for guiding users through scripted processes or making REST calls.
Invocable Methods in Flows