Which type of selling partner must be invited to sell on Amazon.com?

Vendors is the correct answer because vendors must be invited to sell on Amazon.com. Amazon typically invites vendors to become part of its first-party selling model, where the vendor sells directly to Amazon, which in turn resells the products to customers. Unlike third-party sellers, who can register and start selling on Amazon independently through Seller Central, vendors must go through an invitation process and are managed through Vendor Central. This model is often used for larger suppliers and established brands. Sellers, on the other hand, do not require an invitation and can begin selling on Amazon by creating a Seller Central account.