Which statement is true?

1. All squares are rectangles. Rectangles have 4 right angles. Therefore, all squares have 4 right angles.

2. Only some squares are rectangles. Rectangles have 4 sides that are the same length. Therefore, only some squares have 4 sides that are the same length.

3. Only some squares are rectangles. Rectangles have 4 right angles. Therefore, only some squares have 4 right angles.

4. All squares are rectangles. Rectangles have 4 sides that are the same length. Therefore, all squares have 4 sides that are the same length.