Answer:
a. call 9-1-1 or your local emergency number
Explanation:
When someone is injured in the workplace, it is important that you as a co-worker call 9-1-1 or your local emergency number immediately, so that your co-worker receives correct care and avoids suffering complications from the injury .
After calling the emergency service, it is important that you start first aid, so that your friend's injury does not cause further damage before help arrives.