Ta có \(f'\left( x \right) = 2xf(x) \Leftrightarrow \frac{{f'\left( x \right)}}{{f\left( x \right)}} = 2x\)

\( \Rightarrow \int {\frac{{f'\left( x \right)}}{{f\left( x \right)}}dx} = \int 2 xdx \Leftrightarrow \int {\frac{{df\left( x \right)}}{{f\left( x \right)}}} = \int 2 xdx\)

\( \Leftrightarrow \int {\frac{{df\left( x \right)}}{{f\left( x \right)}}} = \int 2 xdx \Rightarrow \ln f\left( x \right) = {x^2} + C \Rightarrow \ln f\left( 0 \right) = C \Rightarrow \ln 2 = C\)

\( \Rightarrow \ln f\left( x \right) = {x^2} + \ln 2 \Leftrightarrow f\left( x \right) = {e^{{x^2} + \ln 2}} \Leftrightarrow f\left( x \right) = 2{e^{{x^2}}}.\)

Vì vậy, \[I = \int\limits_0^1 {{x^3}f\left( x \right){\rm{d}}x} = \int\limits_0^1 {2{x^3}{e^{{x^2}}}{\rm{d}}x} = \int\limits_0^1 {{x^2}{e^{{x^2}}}d\left( {{x^2}} \right)} = \int\limits_0^1 {t{e^t}dt} .\]

Đặt \(\left\{ {\begin{array}{*{20}{l}}{u = t}\\{dv = {e^x}dx}\end{array}} \right.\), ta có \(\left\{ {\begin{array}{*{20}{l}}{du = dt}\\{v = {e^x}}\end{array} \Rightarrow I = \left. {t{e^t}} \right|_0^1 - \int\limits_0^1 {{e^t}dt} = \left. {\left( {t{e^t} - {e^t}} \right)} \right|_0^1 = 1} \right..\) Chọn A.