Which integration method is best for consolidating business processes between two Salesforce organizations?

The most suitable integration method for consolidating business processes between two Salesforce organizations is Salesforce-to-Salesforce integration. This approach specifically facilitates collaboration between different Salesforce instances, allowing for real-time sharing of data, such as accounts, leads, contacts, and custom objects.

Salesforce-to-Salesforce is designed to enhance the efficiency of data sharing and process alignment between businesses leveraging Salesforce, making it ideal for scenarios where two organizations need to maintain synchronization of critical business information, like orders in this case. It leverages the native capabilities of Salesforce, ensuring that data integrity and consistency are maintained seamlessly as it allows users to share and update records in real-time.

In contrast, other integration methods listed, such as Apex callouts, outbound messages, or middleware tools, may involve more complex setups or may not provide the same level of integration within the Salesforce ecosystem. While they can be effective for certain use cases, none offer the native ease of use and direct integration designed specifically for Salesforce-to-Salesforce connectivity. This makes option B the most effective choice for consolidating processes between two Salesforce organizations.