$$\left. \begin{array} { l }
x ( 3 - x ) > 0 \\
( 2 x + 1 ) ( x - 2 ) < 0
\end{array} \right\}$$
If the solution set of the inequality system given above is the open interval $(\mathbf { a } , \mathbf { b })$, what is the difference $\mathbf { a - b }$?\\
A) - 2\\
B) 0\\
C) 1\\
D) $\frac { 1 } { 2 }$\\
E) $\frac { 3 } { 2 }$