Universal Containers (UC) has adopted Salesforce as its primary sales automation tool. UC has 100,000 customers with a g

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Universal Containers (UC) has adopted Salesforce as its primary sales automation tool. UC has 100,000 customers with a growth rate of 10% a year. UC uses an on-premise web-based billing and invoice system that generates over 1 million invoices a year supporting a monthly billing cycle.
The UC sales team needs to be able to pull up a customer record and view their account status, invoice history, and open opportunities without navigating outside of Salesforce.
What should a data architect use to provide the sales team with the required functionality?

A. Create a visual force tab with the billing system encapsulated within an iframe.
B. Create a custom object and migrate the last 12 months of invoice data into Salesforce so it can be displayed on the Account layout.
C. Write an Apex callout and populate a related list to display on the account record.
D. Create a mashup page that will present the billing system records within Salesforce.