Chọn phương án A.

\(\begin{aligned}
\blacksquare&\,\dfrac{2x-1}{3}<-x+1\\
\Leftrightarrow&\,\dfrac{2x-1}{3}+x-1<0\\
\Leftrightarrow&\,\dfrac{2x-1+3(x-1)}{3}<0\\
\Leftrightarrow&\,5x-4<0\\
\Leftrightarrow&\,x<\dfrac{4}{5}\,\,(1)\\
\blacksquare&\,\dfrac{4-3x}{2}<3-x\\
\Leftrightarrow&\,\dfrac{4-3x}{2}+x-3<0\\
\Leftrightarrow&\,\dfrac{4-3x+2(x-3)}{2}<0\\
\Leftrightarrow&\,-x-2<0\\
\Leftrightarrow&\,x>-2\,\,(2)
\end{aligned}\)

Từ (1) và (2) suy ra \(S=\left(-2;\dfrac{4}{5}\right)\).