I got half of it right but I dont know how to do c & d,please help!!!

Guthrie Industries manufactures and sells dog collors. The collars sell for $12 each Information about the company's costs is as follows Variable manufacturing cost per unit Variable selling and administrative cost per unit Fixed manufacturing overhead per month Fixed selling and administrative cost per month $ 250,000 200,000 a. Determine the company's monthly break-even point in units b. Determine the sales volume in dollars) required for a monthly operating income of $900,000, c. Compute the company's morgin of safety if its current monthly sales level is $1,400,000 d. Estimate the amount by which monthly operating income will increase of Guthrie anticipates a $60,000 increase in monthly sales volume 50.000 units 1.800,000 0 Break-even point Sales revenue Margin of safety d increase in operating income