Which is the best definition of a square? a. a 4-sided polygon with all sides equal b. a parallelogram with all sides equal and all angles equal c. a combination of a rectangle and a trapezoid d. a 4-sided polygon with all angles equal

Hello,

The answer should be option B "a parallelogram with all sides equal and all angles equal".

Reason:

The answer is option B because a square is a parallelogram with all sides and angles equal. Its not option A because a square is not a polygon but does have equal sides. Its also not option C because a square is a rectangle but not a trapezoid therefore not combined. Its also not option D because its not a polygon but does have four sides which saying there not equal therefore not the answer. 

If you need anymore help feel free to ask me!

Hope this helps!

~Nonportrit