Three separate slope fields correspond to the differential equation dxdy=ay, where a is a positive constant. At the point (0,1) the approximate slopes of the line elements are measured to be 0.5 in Field I, 1.0 in Field II, and 2.0 in Field III. Which relationship among the parameter values aI,aII,aIII is most consistent with these observations?
a) aI=aII=aIII
b) aI>aII>aIII
c) aI<aII<aIII
d) aI<aIII<aII