The correct answer to this question are choices A and B.
Workflow has been an admin’s friend for a long time. Workflows can update a field, send an email, create a task, and send an outbound message. These can be initiated when a record is created, whenever it meets a certain condition, or whenever it is first set to meet a certain condition. The actions can be performed in any combination and can even have a time delay, rather than be performed immediately. Process Builder also extends upon the things that workflow does.
For updating related records, Process Builder can update any field on any related record, where Workflow can only update some fields on a parent record of a Master-Detail relationship.