\(\int\limits_0^1 {\left( {1 + 3x} \right)f'\left( x \right)dx} = 2019;\,4f\left( 1 \right) - f\left( 0 \right) = 2020.\) Tính \(\int\limits_0^{\frac{1}{3}} {f\left( {3x} \right)dx.} \)
A.\(\dfrac{1}{9}\)
B.\(3\)
C.\(\dfrac{1}{3}\)
D.\(1\)

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