The Laplace transform of the signal u(t-1) * e-2t u(t-1) is ___________

• A. ( frac{e^{-2(s+1)}}{2s+1} )
• B. ( frac{e^{-2(s+1)}}{s+1} )
• C. ( frac{e^{-(s+2)}}{s+2} )
• D. ( frac{e^{-2(s+1)}}{s+2} )