If the position vector of the points $A\:and\:B$ are $\hat i-\hat j+3\hat k$ and $3\hat i+3\hat j+3\hat k$ and the equation of a plane is $\overrightarrow r.(5\hat i+2\hat j-7\hat k)+9=0$, then the points $A\:and\:B$ are?
$\begin{array}{1 1} (a)\:lie\: on\: the\: plane.\:\qquad\:(b)\:are\: on\: the\: same\:side\:of\:the\:plane.\:\qquad\:(c)\:are\:on\:opp.\:sides\:of\:the\:plane.\:\qquad\:(d)\:none\:of\:these \end{array}$