How should anintegration architect integrate the two systems based on the technical requirements and system constraints?

There are 1000 sales reps. Each user processes/creates on average 15 orders per shift. Most of the orders contain 20-30 line items.

How should anintegration architect integrate the two systems based on the technical requirements and system constraints?
A . Use Salesforce external object and OData connector.
B. Use Salesforce custom object, custom REST API and ETL.
C. Use Salesforce standard object, REST API and ETL.
D. Use Salesforce big object, SOAP API and Dataloader.

Answer: C