A refracting surface is represented by the equation `x^(2)+y^(2) = a^(2)`. A ray travelling in negative x-directed towards positive y-direction after reflection from the surface at point P. Then co-ordinates of point P are
A. (0.8 a, 0.6 a)
B. (0.6 a, 0.8 a)
C. `((a)/(2), (a)/(2))`
D. None of these