A second hand car dealer has 6 cars for sale. She decides to investigate the link between the age of the cars, x years, and the mileage, y thousand miles. The date collected from the cars is shown in the table below. Age, x Year 1 2 3 4 5 6 52 74 63 81 90 110 Mileage, y thousand Calculate the a value in the form y= a+ bx O a. 10 Ob 36 O c. 53 O d. 43