Carlos Naturals manufactures bulk quantities of cleaning fluids. The company currently sells 900 containers a month at a sales price of $26 per unit. The addition of a new disinfectant will result in a sales price of $28 per unit for the improved product. It would cost a total of $4,200 per month to make the alteration. Operating income would A. increase by $2,400 B. decline by $2,400 C. decline by $23,400 D. increase by $4,200