Answer:
A polygon is a plane figure.
Step-by-step explanation:
This means it is a 2 dimensional shape that lies flat, it has length and width, it has area but no thickness.
There is no max number of sides, so the first answer is not right.
In math, saying it is solid means its 3-d, so that is not right (it's only 2-d)
Saying its open, means that somewhere on the shape, the sides don't meet up at a corner, like an animal corral with the gate left open. So that's not right. Part of the definition of a polygon is that it is closed.
It is a 2-d shape with straight sides and closed, it lies flat in a plane. The last answer is correct.
