IMHO the examiner is trying to tell you something by specifying a powerful aircraft with VP propellers. For this aircraft In the lower speed ranges you would expect the THP available to be a nearly flat line, although I admit a constant speed prop would give a flatter trace. If you draw THP available as constant over this range and superimpose the power required curve you will see that the maximum power surplus occurs at minimum power speed, Vimp. You have been given this as 95kt
My whole argument relies on having THP available as roughly constant at these speeds, which is a special case. It would not necessarily apply in the real world or to a fixed pitch prop. The shape of the THP available curve (assuming constant EHP) depends on propeller efficiency versus TAS and on your ordinary bugsmasher rises rapidly from zero TAS and then falls off again
This speed is now your best rate of climb speed, Vy. Your best angle of climb speed, Vx, is where you have maximum excess thrust over drag and because props give maximum thrust at very low speed to find Vx you would fly as slowly as possible - minimum control speed is usually quoted
So I go for B
Dick