please explain. thank you

Dybala Corporation produces and sells a single product. Data concerning that product appear below. Per Unit $ 125 75 Selling price Variable expenses Contribution margin Percent of Sales 100% 600 50 408 The company is currently selling 5,260 units per month. Fixed expenses are $210,000 per month. The marketing manager believes that a $7,300 increase in the monthly advertising budget would result in a 300 unit increase in monthly sales. What should be the overall effect on the company's monthly net operating income of this change? Multiple Choice increase of $7,700 decrease of $7,300 Increase of $15,000 decrease of $7,700