Tính \(I = \int\limits_0^1 {{{\rm{e}}^{3x}}.{\rm{d}}x} \)

A. \(I = {{\rm{e}}^3} - 1\)

B. \(I=e-1\)

C. \(I = \frac{{{{\rm{e}}^3} - 1}}{3}\)

D. \(I = {{\rm{e}}^3} + \frac{1}{2}\)