Which of the following statements is INCORRECT?

Options

A. All rhombuses are parallelograms.
B. All squares are not parallelograms.
C. All rectangles are not squares.
D. All rhombuses are not squares.

Answer

To solve the question of identifying the incorrect statement among the options provided regarding the properties of quadrilaterals (specifically rhombus, square, and rectangle), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- **Square**: A quadrilateral with all sides equal and all angles equal to 90 degrees.
- **Rectangle**: A quadrilateral with opposite sides equal and all angles equal to 90 degrees.
- **Rhombus**: A quadrilateral with all sides equal, but angles are not necessarily 90 degrees.
- **Parallelogram**: A quadrilateral where opposite sides are parallel and equal.

2. **Analyze Each Statement**:
- **Statement 1**: "All squares are parallelograms."
- This is **True** because a square has opposite sides that are equal and parallel.
- **Statement 2**: "All rectangles are squares."
- This is **False** because while all squares are rectangles, not all rectangles are squares (rectangles can have unequal adjacent sides).
- **Statement 3**: "All rhombuses are squares."
- This is **False** because a rhombus does not have to have 90-degree angles; it only requires all sides to be equal.
- **Statement 4**: "All rhombuses are parallelograms."
- This is **True** because a rhombus satisfies the properties of a parallelogram.

3. **Identify the Incorrect Statement**:
- From the analysis, we see that the statements "All rectangles are squares" and "All rhombuses are squares" are incorrect. However, since we need to choose one, we can conclude that "All rectangles are squares" is the most straightforward incorrect statement.

### Conclusion:
The incorrect statement is: **"All rectangles are squares."**