To determine which option is not a characteristic of all parallelograms, we should first understand the defining properties of parallelograms. All parallelograms possess two pairs of opposite sides that are parallel and equal in length. Additionally, opposite angles in a parallelogram are equal, and the diagonals bisect each other.
If an option states that a parallelogram has four right angles, it is important to note that while rectangles (which are a type of parallelogram) have this characteristic, not all parallelograms do. Therefore, if the question presents options including having four right angles, that would be the correct choice as it does not apply to all parallelograms.