Net market value means:

(a) Except as provided in paragraph (b)and (c) of this section, the value found by multiplying the net market price by the appropriate quantity of the volumetric units or the minimum value in a production contract received by a producer for sorghum after adjustments for any premium or discount.

(b) For imported sorghum, the total value paid by the importer for the sorghum as reported on the appropriate Customs form; or

(c) For sorghum pledged as collateral for a loan issued under any Commodity Credit Corporation price support loan program, the principal amount of the loan.