The Lorax Computer Products produces two keyboards, Regular and Special. Regular keyboards have a unit contribution margin of 150, and Special keyboards have a unit contribution margin of 750. The demand for Regulars exceeds Computer Products' production capacity, which is limited by available machine-hours and direct manufacturing labour hours. The maximum demand for Special keyboards is 100 per month. Management desires a product mix that will maximize the contribution toward fixed costs and profits. Direct manufacturing labour is limited to 2,200 hours a month and machine hours are limited to 800 a month. The Regular keyboards require 15 hours of labour and 9 machine hours. Special keyboards require 30 labour hours and 18 machine hours. Select the appropriate linear programming objective and constraint functions designed to maximize Computer Products total contribution margin. Let R represent Regular keyboards and S represent Special keyboards. a. Maximize: $750S + $150R Constraints: Labour hours: 15R + 9S 2,200 Machine hours: 30R 18S800 Special: S 100 S O Regular: R0 b. Maximize: $150R +$750S Labour hours: 15R + 30S 2,200 Constraints: Machine hours: 9R + 18S 800 Special: S 100 S O Regular: R 0 Maximize: $150R + $750S Labour hours: 15R + 30S 2,200 Constraints: Machine hours: 9R + 18S 800 Special: S100 S 0 Regular: R 0 d. Maximize: $750S + $150R Labour hours: 15R + 30S 2,200 Constraints: Machine hours: 9R + 18S 800 Special: S 100 S O Regular: R0