Universal Container’s Sales Ops manager wants a process in place where every United Kingdom based accounts should fall into one of the five different districts that are required to be created as well. The account field should also be inherited by the opportunity. Which of the following would help the Salesforce Admin to accomplish all this?

Answer options:

A.Workflow Field Update
B.Validation Rule
C.Auto-response Rule
D.Escalation Rule

Correct Answer: A 
Workflow field update will help in automating the field value. Workflow field update is one of the workflow actions that will give the ability to automate a field value. 
Option B is incorrect because the validation rule doesn’t have the option to do any field update. 
Option C is incorrect because auto-response rule is a set of conditions to send the automatic email responses to lead or case submissions based on the attributes of the submitted record. 
Option D is incorrect because escalation rule automatically reroutes a case and can notify a user if the case remains open even after a certain period.
Reference: 

https://help.salesforce.com/articleView?id=workflow_managing_field_updates.htm&type=5