The dimensions of a room whose length is $3$ m more than its breadth,if the area of the room is $70$ sq.m.The quadratic equation to find the dimensions of the room is _____

Question

$\begin{array}{1 1}(A) \; x^2-3x+70=0\\(B)\;x^2-3x-70=0\\(C)\;x^2+3x-70=0 \\(D)\;x^2+3x+70=0 \end{array}$