The correct answer is option 'D' which is a quadrilateral.

Quadrilaterals are closed figures that have four sides. They can have different shapes and angles, but they all have four sides. Here is an explanation of the different types of quadrilaterals:

1. Square:
- A square is a type of quadrilateral where all four sides are equal in length.
- Additionally, all four angles in a square are right angles (90 degrees).
- The opposite sides of a square are parallel and congruent.

2. Rectangle:
- A rectangle is a quadrilateral where opposite sides are parallel and congruent.
- All four angles in a rectangle are right angles (90 degrees).
- Unlike a square, a rectangle does not have all sides equal in length.

3. Parallelogram:
- A parallelogram is a quadrilateral where opposite sides are parallel and congruent.
- The opposite angles in a parallelogram are also congruent.
- However, the sides of a parallelogram are not necessarily equal in length.

4. Rhombus:
- A rhombus is a quadrilateral where all four sides are equal in length.
- Unlike a square, the angles in a rhombus are not necessarily right angles.
- The opposite angles in a rhombus are congruent, but the adjacent angles are not.

5. Trapezoid:
- A trapezoid is a quadrilateral with one pair of parallel sides.
- The non-parallel sides of a trapezoid are not equal in length.
- The angles in a trapezoid can vary in size.

These are just a few examples of quadrilaterals. There are other types as well, such as kites and irregular quadrilaterals, which do not fit into any specific category. However, they all share the common characteristic of having four sides.

In conclusion, a quadrilateral is a closed figure with four sides. It can have different shapes and angles, including squares, rectangles, parallelograms, rhombuses, and trapezoids.