The correct answer is C, leverage Salesforce Connect to bring the order line item from the legacy system to Salesforce. Salesforce Connect is a feature that allows you to integrate external data sources with Salesforce and access them in real time without copying or synchronizing the data. This way, the sales team can view the order status from the ERP system without having access to it. Leveraging Canvas, building batch jobs, or building real-time integration are also possible solutions, but they are more complex and costly than using Salesforce Connect.