Universal Container finance department has requested from the Salesforce admin to establish case rules so that billing cases are routed to the correct queue. How can the Salesforce admin achieve this?

Answer options:

A.Create Assignment Rules
B.Create Workflow Rule
C.Create Process Builder
D.Create formula field

Correct Answer: A 
 Assignment rules define conditions that determine how leads or cases are processed. From setup access Queues in the quick find box then select queues the click new and complete all the details for a new queue then add queue members. Then Then add a new rule entry to the Standard Case Assignment rule to route billing cases to the Billing Support Agents queue. 
Option B is incorrect because workflow is a way to automate certain business processes. You can create a rule and based on certain criteria that you set. 
Option C is incorrect because process builder is a point-and-click tool that lets you easily automate if/then business processes and see a graphical representation of your process as you build it. 
Option D is incorrect because formula fields are read only field whose value is evaluated from the formula or expression defined by us. 
References: 

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