One material is used in the manufacture of product X. The total cost of the material (purchased and used) in a period was $4,000. In the period, the direct material price and usage variances were $200 adverse and $300 favourable respectively and 1,000 units were manufactured. What is the standard direct material cost per unit for product X? O 0 O 0 $3.90 $4.30 $4.10 $3.80