How should an app builder solution this request?

DreamHouse Realty wants to make sure an Opportunity has a field Expected_Close_Date_c populated before it is allowed to enter the qualified stage.

How should an app builder solution this request?
A . Record Type
B . Validation Rule
C . Activity History
D . Page Layout

Answer: B

Explanation:

A validation rule is a formula that evaluates the data in one or more fields and returns a value of “True” or “False”. Validation rules verify that the data a user enters in a record meets the standards you specify before the user can save the record. In this case, a validation rule can be used to check if the Expected_Close_Date_c field is populated before the Opportunity stage is set to qualified