Which has more lines of symmetry a square or an rectangle?

All squares are rectangle, but not all rectangles are square.

The expected answer is "a square" ...

A square has 4 lines of symmetry. A rectangle that is not a square has 2 lines of symmetry. However, the question is ambiguous. Since a square is a rectangle you can say that some rectangles have 4 lines of symmetry. A better question is, "Which has more lines of symmetry; a square, or a rectangle that is not a square?"