D is the best choice because y would be the total amount of money he would have to pay. X would be the amount of hours he uses the phone and the hourly fee is 23 so it would be 23x. the flat fee was 16 so you just add that on to the hourly fee. The whole equation should be y = 23x + 16
By process of elimination and plugging in the math we can say that Jack earns 8.25 an hour by multiplying 2*8.25=16.50. Isa must then earn 9.50, therefore she earns a greater hourly pay then Jack as a result
