Answer
(c) \( (2, 2,1) \).
Work Step by Step
When light reflects off a smooth surface, the angle of incidence equals the angle of reflection. Given that the point of incidence is \( (1,1,0) \) and the incident ray originates from \( (0,0,1) \), the reflected ray will continue in the direction symmetrically opposite to the incident ray with respect to the normal at the point of incidence. Since the surface is in the xy-plane, the normal at \( (1,1,0) \) is in the direction of the z-axis, and hence the reflected ray will pass through the point \( (2,2,1) \).
