Publish command message is sent from

The correct answer is: C. publisher to broker and broker to publisher.

A publish command message is sent from a publisher to a broker, and the broker then sends the message to all subscribers.

Option A is incorrect because the broker does not send the message to the publisher.

Option B is incorrect because the publisher does not send the message to the broker.

Option D is incorrect because the server does not send the message to the client.