Which figure can serve as a counterexample to the conjecture below?
if one pair of opposite sides of a quadrilateral is parallel, the the quadrilateral is a parallelogram.
a. rectangle
b. rhombus
c. square
d. trapezoid

When we say conjecture, in math, this is defined as a statement that appears to be true but is not yet proven. Now, the question asked for the counterexample, which means, the opposite of the given statement above. Rectangle, rhombus and square are considered parallelograms. Therefore, the figure that can serve as a counterexample to the conjecture given is the TRAPEZOID. The answer would be option D.

Understanding what? lol