Universal Containers (UC) has a partner community for its 200 distributors.

Sharing Sets in Partner Communities:

Sharing Sets allow sharing of records with users in specific profiles, based on a common field value between the user and the record.

Why Option C is Correct:

A Sharing Set can be configured to grant access to Delivery records where the distributor matches a custom field on the record. This is a scalable solution for partner communities.

Why Others Are Incorrect:

Option A: Role Hierarchies are limited to three levels for partner users, and this approach does not scale well for 200 distributors.

Option B: Using two sharing rules adds unnecessary complexity and may not handle all scenarios effectively.

For details on Sharing Sets, see Salesforce Partner Community Sharing documentation: https://help.salesforce.com/