WHICH GRAPH REPRESENTS A FUNCTION? NEed HELP PLEASE I DONT GET IT

Which is a true statement about an exterior angle of a triangle a. it is formed by two segments that are not sides of the triangle, b. it forms a linear pair with one of the interior angles of the triangle, c. it is complementary to one of the interior angles of the triangle. d. it is formed by two segments that are sides of the triangle.

The graph below represents the number of dolphins in a dolphin sanctuary. select all the key features of this function.

True or false? a circle could be circumscribed about the quadrilateral below.