A student claims that the angle of incidence of a sound ray on a wall is measured between the ray and the wall itself. Which statement correctly rectifies this claim?
(a) Angle of incidence is measured between the incident ray and the normal to the wall.
(b) Angle of incidence is measured between the incident ray and the wall.
(c) Angle of incidence is the angle between incident and reflected rays.
(d) Angle of incidence is always 90∘ minus the angle with the normal.