A square's sides are shrinking at a constant rate of $2\text{ cm/s}$. What is the rate at which the length of the square's diagonal is changing?

• A. $-2\sqrt{2}\text{ cm/s}$
• B. $-\sqrt{2}\text{ cm/s}$
• C. $-4\text{ cm/s}$
• D. $-2\text{ cm/s}$