Universal Container’s HR department requested the Salesforce Admin to send an employee A time off request for the user manager to sign off from it and take an action? Which functionality will help the Salesforce Admin to achieve the HR needs?

Answer options:

A.Flow Builder
B.Process Builder
C.Workflow Rules
D.Approval Process

Correct Answer: D 
Approval Process provides automation on how Salesforce records get approved. Through an approval process, you specify the steps required for a record to get approved and who should provide the approval at each stage. 
Options A, B, and C are incorrect because they don’t have the ability to have records approved through the standard wizard as the approval process works. Although they are automation tools, they don’t have these functionalities. On the other hand, you can have a process builder included with them while doing any automation that requires approvals. 
Reference: 

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