What is the appropriate publish/subscribe logic to meet these requirements?

Universal Containers (UC) decided it will not to send emails to support personnel directly from Salesforce in the event that an unhandled exception occurs. Instead, UC wants an external system be notified of the error.

What is the appropriate publish/subscribe logic to meet these requirements?
A . Publish the error event using the addError() method and have the external system subscribe to the event using Comet
C . Publish the error event using the Eventbus.publish() method and have the external system subscribe to the event using Comet
E . Have the external system subscribe to the BatchApexError event, no publishing is necessary.
F . Publish the error event using the addError() method and write a trigger to subscribe to the event and notify the external system.

Answer: B