The correct option to describe a rectangle is:

C. Opposite sides are parallel

Explanation:

• A rectangle has four right angles (90° each), so option A ("All angles are acute") is incorrect.
• Opposite sides of a rectangle are not perpendicular to each other but are parallel, so option B ("Opposite sides are perpendicular") is incorrect.
• Opposite sides are parallel in a rectangle, which makes option C correct.
• All sides of a rectangle do not have to be the same length; only opposite sides are equal. This means option D ("All sides are the same length") describes a square, not a rectangle.

Would you like further details or have any questions about this?

Here are 5 related questions for further understanding:

1. What is the difference between a rectangle and a square?
2. Can a rectangle have any acute angles?
3. How is the area of a rectangle calculated?
4. Are diagonals in a rectangle equal?
5. What is the relationship between the diagonals of a rectangle?

Tip: In a rectangle, diagonals are always equal and bisect each other.