12. Which shape could be sorted into a group of quadrilaterals or a group of parallelograms? (A) Hexagon (B) Triangle (C) Rhombus (D) Trapezoid

1. A quadrilateral is any four-sided polygon, while a parallelogram is a special type of quadrilateral in which both pairs of opposite sides are parallel. 2. Option (A), a hexagon, has six sides, so it is not a quadrilateral. 3. Option (B), a triangle, has three sides, so it is not a quadrilateral. 4. Option (C), a rhombus, is a quadrilateral where all four sides have equal length and opposite sides are parallel, making it a type of parallelogram. 5. Option (D), a trapezoid, is a quadrilateral with at least one pair of parallel sides; however, it is not necessarily a parallelogram because the other pair of sides might not be parallel. Thus, the shape that fits into both groups (quadrilaterals and parallelograms) is the rhombus. The answer is \( \boxed{C} \).