# Two sides of a rhombus are along the lines, $x−y+1=0$ and $7x−y−5=0$. If its diagonals intersect at $(−1, −2)$, then which one of the following is a vertex of this rhombus ?
( A ) $(-3, -9) ( B )$(-\frac{10}{3}, -\frac{7}{3})$( C )$(-3, -8)$( D )$(\frac{1}{3}, -\frac{8}{3})\$