There are exempted from the computation of the amount of the sales tax the gross receipts from any sale of tangible personal property which is shipped to a point outside this county pursuant to the contract of sale by delivery by the vendor to such point by means of:
A. Facilities operated by the vendor;
B. Delivery by the vendor to a carrier for shipment to a consignee at such point; or
C. Delivery by the vendor to a customs broker or forwarding agent for shipment outside this county. (MC Ord. 39A §66, 1971)