$.$Under absorption costing $($AC$),$ fixed manufacturing overhead costs are accounted for as product costs. $$Which of the following is an argument in support of the use of absorption costing $($AC$)?$

a$.$

Absorption costing $($AC$)$ understates the balance sheet & income statement.

b$.$

Variable manufacturing overhead is a period cost.

c$.$

Fixed manufacturing overhead is difficult to allocate properly.

d$.$

Fixed manufacturing overhead is necessary for the production of a product.

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