Exam Certified Sharing and Visibility Architect topic 1 question 10 discussion

I disagree with D. A sharing set would only grant access to records associated to the partner account that the partner user is associated with, not to other records (and child records) they own. They are typically meant for customer portal users and not partner portal users. https://trailhead.salesforce.com/content/learn/projects/communities_share_crm_data/external_user_sharing C for sure is incorrect as flip flopping record ownership is a bad design. B could be done, but the way the question is worded, all of the partner users (individual distrubutors) are from the same distro company, so the role hierarchy should be available without adding additional complexity. A seems like the correct choice, though it assumes that there's some sort of indicator on the delivery record that ties it to the distributor (cross reference fields are not available).