The Product Questions add-on enables email messages with product questions to be sent to the proper product owner in X-Cart Marketplace:
If a vendor owns the product, the message is sent to the vendor.
If the product is owned by an administrator acting as a vendor, the message is sent to them, respectively.
In the store's back-end, the product owner can answer questions about their products, and the answers are shown to the customers with the name of the product owner attached to them.
Vendor answer in the Vendor area
Vendor answer on the storefront