If $x=\large\frac{2}{3}$ and $x=-3$ are the roots of the equation $ax^2+7x+b=0$,then the values of $a$ and $b$ are _______

Question

$\begin{array}{1 1}(A) \; a=3,b=6\\(B)\;a=-3,b=-6 \\(C)\;a=3,b=-6 \\(D)\;a=-3,b=6 \end{array}$