Answer:
Option D. Saturation Point
Step-by-step explanation:
The reason is that the demand of the market can not be increased further at a given price if it is already at peak. This is because everybody desire limited number of product. Just take the example of pizza, you can not eat 10 pizza at a time because you can only eat 3 slice of it. So the point at which the sales doesnot get affected by the increase in advertisments is saturation point.