please answer this question quick (will like up)

Sage Company is operating at 90% of capacity and is currently purchasing a part used in its manufacturing operations for $15.00 per unit. The unit cost for the business to make the part is $21.00, including fixed costs, and $11.00, not including fixed costs. If 34,941 units of the part are normally purchased during the year but could be manufactured using unused capacity, the amount of differential cost increase or decrease from making the part rather than purchasing it would be a Os. $209,646 cost increase b. $S24.115 cost decrease Od $139,764 cost increase Od. 5139,764 cost decrease