10 of 18 (0 co This Test: 18 pts The variable cost of Part X is $50 per unit and the full cost of the part is $80 per unit. The part is produced in County Z and transferred to a plant in Country B.Country Zhas a 10% income tax rato. Country B has a50% inome tax rate and an importa ty equal to variable cost Assume Part X is transferred at full cost. By using full cost instead of variable cost of the itom. Part X can be transferred at full cost or 10% for the transfer price, the inoome tax effect per unit in Country Bis O A. OB, O C. O D. a decrease in tax by $15 per unit adecrease in tax by $9 per unit an increase in tax by $15 per unit an increase in tax by $9 per unit