Which two approaches should the Architect take?

DreamHouseRealty has an integration that creates records in a Salesforce Custom Object.

The Custom Object has a field marked as required on the page layout.

Dream House Realty has noticed that many of the records coming from the external system are missing data in this field.

The Architect needs to ensure this field always contains data coming from the source system.

Which two approaches should the Architect take? Choose 2 answers
A . Set up a Validation Rule to prevent blank values.
B. Create a Workflow to default a value into this field.
C. Mark the field required in setup at the field level.
D. Blame the customer’s external system for bad data.

Answer: A,C