Final answer:
The topic in question is Physics, specifically Light Reflection. The law of reflection states that the angle of reflection equals the angle of incidence. Therefore, if the angle of incidence is 40 degrees, the angle of reflection is also 40 degrees by this law.
Step-by-step explanation:
When a ray of light approaches a smooth polished surface and the light ray bounces back, it is called the reflection of light. The incident light ray that land on the surface is reflected off the surface. The ray that bounces back is called the reflected ray. If a perpendicular were drawn on a reflecting surface, it would be called normal. The figure below shows the reflection of an incident beam on a plane mirror.
The field dealing with the question you've asked is Physics. Specifically, this pertains to the concept of Light Reflection. According to the law of reflection, the angle of reflection is equal to the angle of incidence. This law is always true, irrespective of the type of surface (smooth or rough), type of mirror (plane, concave, or convex), or any other characteristics of the reflecting surface or the incident light.
So, when your question asks what the angle of reflection would be when the angle of incidence is 40 Degrees, it's using this law. Given this, the answer would be 40 Degrees (option A). Just to confirm, this means the light ray would get reflected in such a way that it forms a 40-degree angle with the normal (i.e., the line perpendicular to the surface at the point where the ray strikes the surface).
Learn more about Light Reflection