The amount Bryce earns babysitting in a month is represented by the equation a=10.5h. In the equation, a represents the total amount Bryce earns. The number of hours he babysits is represented by h. What is the constant of proportionality (unit rate) of a to h? A. 10.50/hr B.10.00/hr C.9.50/hr D.5.10/hr