You are missing the point of the question.
Vx is greater than Vs.
Vx is the speed at which angle of climb is best.
Vy is the speed at which rate of climb is best.
Vy is greater than Vx.
So our sped range is
Low speed...Vs.............Vx.............Vy...........High speed
In this question we are decelerating from Vy (at which ROC is best), through Vx (at which angle of climb is best) to Vs (at which we stall).
This will cause the angle of climb to increase (until we reach Vx) then to decrease (until we stall).