B is the correct answer.

The correct answer is:
✅ B. Include the Shipments tab on the app's navigation bar.

Explanation

Split list views are available for standard and custom objects in Lightning Experience, including the Salesforce mobile app.
To allow the team to use split view for Shipments, the object must be accessible in the app.
Adding the Shipments tab to the app’s navigation bar ensures users can access the object and use split view.

Correct Answer: B. Include the Shipments tab on the app's navigation bar
A. Filter by a single shipment record type in the list view. ❌ Not relevant, filtering doesn’t enable split view.
B. Include the Shipments tab on the app's navigation bar. ✅ Correct — Split View only works if the object has a tab in the navigation bar.
C. Split views are only available on standard objects. ❌ Wrong — they work for both standard and custom objects.
D. Add the Manage List Views permission for support users. ❌ Wrong — they already can use list views, no special permission needed for split view.

I agree the answer is B

it's B. Split list views require the secondary object to have a tab in the app's navigation bar to be available as an option.