Orchestrator alerts are real-time notifications related to robots, queue items, triggers, and more. Alerts can have one of the following severity levels, which indicate the importance and impact of the events1:
Info - notifies you about low importance events, that do not interrupt the process execution, such as robots becoming available, users being assigned as reviewers, etc.
Success - notifies you about a successful status, such as a job being completed, a queue item being processed, etc.
Warn - notifies you about possible risky events that may interrupt your process execution, but any interruption can be recovered, such as queue items failing with business exceptions, triggers not being able to create new jobs, etc.
Error - notifies you about imminent risky events that prevent the process from executing successfully, such as jobs failing, robots not responding, queue items failing with application exceptions, etc.
Fatal - notifies you about events that force-stop the process execution, such as robots going offline or being disconnected, etc.
Option A is the correct answer, as it lists the five severity levels of Orchestrator alerts as defined in the documentation1. Option B is incorrect, because there is no Critical severity level, but rather Fatal. Option C is incorrect, because there are no Information, Complete, or Failure severity levels, but rather Info, Success, and Fatal. Option D is incorrect, because there are no Completed or Fatal severity levels, but rather Success and Fatal.
References: 1: Alerts Overview