i know the answer is C but i would like to know how they got that answer. thank u!

4. LO 5 Kuskela Company makes hats in three size: small, medium and large, Medium hats have shown a loss for Small Sales $125,000 Variable costs 50,000 Contribution margin 75,000 Fixed costs 70,000 Operating income $ 5,000 several years, similar to the operating loss shown in the following table: Medium Large Total $175,000 $250,000 $550,000 100,000 150,000 300,000 7 5,000 100,000 250,000 80,000 85,000 235,000 $ (5,000) $ 15,000 $ 15,000 Of the total $235,000 in fixed costs, $180,000 is common costs that have been allocated equally to each product line. What will total operating income be if medium hats are dropped? a. $175,000) b. $(55,000) C. $(40,000) d. $20,000