A ) A square and a parallelogram are quadrilaterals. [This is correct as they all have four sides.]
B ) Opposite sides of a square and a parallelogram are parallel. [This is correct as the sides are all parallel.]
C ) A trapezoid has one pair of parallel sides. [This is correct as the trapezoid has one parallel side and another side which is slanting inwards or outwards.]
D ) All the above. [All that makes this answer correct.]
No, I do not agree. For some of the parallelograms , one pair of parallel sides are not the same as the other pair
BFDE is a parallelogram because BF is parallel to DE and BE is parallel to FD. which shows that it is a parallelogram as all the sides are parallel to each other.