B： Extending the B2C Commerce storefront to trigger emails via Marketing Cloud's journey REST APIs allows the customer to send triggered emails based on customer behavior on the storefront, such as signing up, placing an order, or abandoning a cart. The REST APIs can also pass data attributes, such as order details or personalization information, to Marketing Cloud. D. Copying and pasting the Collect Script within the head or body in the website template allows the customer to track customer behavior on the storefront using Marketing Cloud's Web & Mobile Analytics feature. The Collect Script can also capture customer attributes, such as email address or contact key, and send them to Marketing Cloud. E. Updating order.export custom object in B2C Commerce with the Marketing Cloud object data extension allows the customer to map order data from B2C Commerce to Marketing Cloud using a point-and-click configuration in Business Manager.
This enables order data synchronization between B2C Commerce and Marketing Cloud. References:
https://developer.salesforce.com/docs/commerce/sfra/marketing-cloud/marketing-cloud-integration
https://developer.salesforce.com/docs/commerce/sfra/marketing-cloud/transactional-messaging-api
https://help.salesforce.com/s/articleView?id=sf.mc_pb_web_and_mobile_analytics.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.mc_co_data_integration_with_commerce_cloud.htm&type=5