From the given graph, the image is a trapezoid.
Therefore,
The first option, "the polygon is a rectangle" is incorrect.
The second option "Adjacent sides of the polygon are perpendicular." cannot be true as well because trapezoid has one the adjacent sides which is not perpendicular.
Third option" Opposite sides of the polygon are parallel", this can't be true as well because only two sides are parallel.
Fourth option " The slope of side c is 0.", this is true because line c is a horizontal line with zero rise and maximum run. Therefore,
Slope = 0 ÷ 9
= 0