The Laplace transform of a function f(x) is the function L[f(s)] of the variable s defined by the improper integral:
a. ∫(0 to [infinity]) e^(-st) f(t) dt
b. ∫(0 to [infinity]) e^(st) f(t) dt
c. ∫(-[infinity] to [infinity]) e^(-st) f(t) dt
d. ∫(-[infinity] to [infinity]) e^(st) f(t) dt