MicroBrush Co. manufactures electric toothbrushes. Each toothbrush requires a small motor, Part M4. MicroBrush is currently manufacturing the motor, but another company, RotorWorld, has offered to supply it for $11 per motor. Each motor requires $2.00 of direct materials, $4.00 of direct labor, $3.00 of variable manufacturing overhead, and $1.50 of fixed manufacturing overhead. If MicroBrush accepts RotorWorlds offer, all fixed manufacturing overhead costs will continue. What should MicroBrush do?

• A : Buy Part M4 because it will save $2.00 per unit.

• B : Buy Part M4 because it will save $0.50 per unit.

• C : Make Part M4 because it will save $5.00 per unit.

• D : Make Part M4 because it will save $2.00 per unit.