Universal Container would like to automate cases coming to Salesforce since they don’t have any assignment rule within their system. They would like their services and support team to work on to take ownership and work on the cases whenever they can. How can Salesforce admin resolve this issue?

Answer options:

A.Use Auto response rules
B.Use Escalation Rules
C.Implement Cases Queue and have a default owner assigned in place
D.Implement Cases Queue and create a validation rule to update the default owner

Correct Answer: C 
Case queues in Salesforce provide your support organization with an easy, flexible solution to support and distribute the cases across different levels of the organization. You can create multiple queues for your different support tiers and assign cases to those queues manually or automatically with case assignment rules. When you’ve defined a queue, Salesforce automatically creates a queue list view that will be available to queue members on the Cases home page. Additionally, you can now leverage your case queue with assignment rules.
Option A is incorrect because auto-response rule is a set of conditions for sending automatic email responses to lead or case submissions based on the attributes of the submitted record. 
Option B is incorrect because escalation rule automatically reroutes a case and can notify a user if the case remains open after a certain period has passed.
Option D is incorrect because validation rule is not responsible for any assignments. Validation rules verify that data entered by users in records meet the standards you specify before they can save it 
Reference: 

https://trailhead.salesforce.com/en/content/learn/modules/service_basics/service_basics_automate_case_management