For the Laplace transform of a signal X(s) = 1/s+2 + 1/s+4, which one of the following is the correct statement is the correct statement regarding is poles and zeroes?
a. poles at 2 and 4, zeros at 3 and infinity
b. poles at -2 and -4, zeros at -3 and infinity
c. poles at 2, 4 and infinity; zeros at 3
d. poles at 2, -4 and infinity; zeros at -3
