If in triangle `A B C ,A-=(1,10),` circumcentre `-=(-1/3,2/3)` and orthocentre `-=((11)/3,4/3)` then the co-ordinates of mid-point of side opposite to `A` is `(1,-(11)/3)` (b) (1, 5 ) (c) `(1,-3)` (d) (1, 6)