A linear time-invariant system initially at rest, when subjected to a unit-step input, gives a response y(t) = te-t, t > 0. The transfer function of the system is:

• A. \(\frac{1}{{{{\left( {s + 1} \right)}^2}}}\)
• B. \(\frac{1}{{{{s\left( {s + 1} \right)}^2}}}\)
• C. \(\frac{s}{{{{\left( {s + 1} \right)}^2}}}\)
• D. \(\frac{1}{{s + 1}}\)