From the following data calculate the level of performance of Ray, Joy, and Hay using Merrick Differential Piece Rate System. Normal rate per unit is RO 15, Working hours per day are 6 hours, Standard time per unit is 20 seconds, and Output is as follows: Ray 1,000 units, Joy 1,200 units, and Hay 1,500 units. a. Ray Earnings is 138.89%, Joy Earnings is 111.11% and Hay Earnings 92.59% b. Ray Earnings is 111.11%, Joy Earnings is 92.59%, and Hay Earnings 138.89% Ray Earnings is 92.59%, Joy Earnings is 138.89% and Hay Earnings 111.11% d. Ray Earnings is 92.59%, Joy Earnings is 111.11% and Hay Earnings 138.89% C