10.If u (t) = 1 for t >= 0 and u (t) = 0 for t < 0, determine the Laplace transform of [u (t) u (t a)].

• A. 1/s(1+e^(-as))
• B. 1/s(1-e^(-as))
• C. 1/s(1+e^as)
• D. 1/s(1-e^as)