Which of the following is not acceptable for accounting for by products?
A、Net realisable value of the by product is deducted from the cost of the main product.
B、Pre-separation costs are apportioned to the by product to calculate its profit.
C、Sales value of the by-product is deducted from the cost of the main product.
D、By-product income less post-separation costs is added to the sales of the main product.