X(z) is the z-transform of the signal x(n), then what is the z-transform of the signal nx(n)?

• A. \(-z\frac{dX(z)}{dz}\)
• B. \(z\frac{dX(z)}{dz}\)
• C. \(-z^{-1}\frac{dX(z)}{dz}\)
• D. \(z^{-1}\frac{dX(z)}{dz}\)