1. For the purpose of the proper administration of this chapter and to prevent evasion of the sales tax, it is presumed that all gross receipts are subject to the tax until the contrary is established. The burden of proving that a sale of tangible personal property is not a sale at retail is upon the person who makes the sale unless the person takes from the purchaser a certificate to the effect that the property is purchased for resale and the purchaser:
(a) Is engaged in the business of selling tangible personal property;
(b) Is registered pursuant to NRS 360B.200 or holds a permit issued pursuant to NRS 360.5973; and
(c) At the time of purchasing the property, intends to sell it in the regular course of business or is unable to ascertain at the time of purchase whether the property will be sold or will be used for some other purpose.
2. If a sale of tangible personal property is transacted by drop shipment, the third-party vendor is relieved of the burden of proving that the sale is not a sale at retail if:
(a) The third-party vendor:
(1) Takes from his or her customer a certificate to the effect that the property is purchased for resale; or
(2) Obtains any other evidence acceptable to the Department that the property is purchased for resale; and
(b) His or her customer:
(1) Is engaged in the business of selling tangible personal property; and
(2) Is selling the property in the regular course of business.