Please explain!! Thank You

A company distributes a product that sells for $50 per unit. Variable expenses are $10 per unit, and fixed expenses total $15,000 annually. Assume that the company sold 4,000 units last year. The sales manager is convinced that a 10% reduction in the selling price, combined with a $30,000 increase in advertising expenditures, would increase annual unit sales by 50%. If these changes were made, by how much would net operating income increase or decrease? a. $20,000 increase b. $16,000 increase c. $12,000 decrease d. $10,000 decrease e. None of the above The following information pertains to a company's CVP relationships: Breakeven point in units sold 1,000 Variable cost per unit $500 Total fixed costs $250,000 How much will be contributed to profit by the 1,001^st unit sold? a. $1 b. $500 c. $750 d. $250 e. $1,000