Answer :
One of the most common causes of a materials price variance is an unexpected change in raw materials costs (A).
Raw material is the basic material from which a product is made. Raw material costs can change unexpectedly which causes a material price variance. This material price variance happens when there is a difference between the actual price paid for materials in production and the standard price of the material. Of course this difference will not be favorable if the actual price paid is higher than the standard price. Various factors may contribute to this unexpected price change, including a price increase, transportation expenses, or the quality of materials.
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