A linear system at rest is subject to an input signal r(t) = 1 - e^(-t). The response of the system for t > 0 is given by c(t) = 1 - e^(-2t). The transfer function of the system is: Select one:
a. 2(s + 1)/(s + 2)
b. (s + 1)/(s + 2)
c. (s + 1)/(2(s + 2))
d. (s + 2)/(s + 1)