Scorpion Production Company planned to use 1 yard of plastic per unit budgeted at $81 a yard. However , the plastic actually cost $80 per yard. The company actually made 3,900 units, although it had planned to ,make only 3,300 units. Total yards used for production were 3,960. How much is the total materials variance? a. $48,600 U b. $4,860 U c. $3,960 F d. $900 U