please help and please be detailed

Increase in sales (2) How much will a company's net operating income change if it undertakes an advertising campaign given the following data: [hint: Use the CM ratio) Cost of advertising campaign $ 25,000 Variable expense as a percentage of sales 42 % $ 60,000 A) $200 increase B) $25,200 increase C) $15,000 increase D) $9,800 increase