I have a Cloud Run FastAPI app that subscribes to a PubSub subscription. It’s going to handle bursty traffic, so there may be zero instances or there may be 20 at a given time.

Let’s say I have 10 containers running and a message gets published. Does the message

a.) get sent to all 10 container subscribers

b.) gets sent to one of the known subscribers, and assuming it gets ACK’d, doesn’t get sent to others

c.) something else?

Based on my reading of the documentation I believe it’s option B but can’t find anything that explicitly confirms the behavior. If it isn’t behaving as option B does, is there a way to get it to?