Let `k` be an integer such that the triangle with vertices `(k ,-3k),(5, k)` and `(-k ,2)` has area `28s qdot` units. Then the orthocentre of this triangle is at the point : `(1,-3/4)` (2) `(2,1/2)` (3) `(2,-1/2)` (4) `(1,3/4)`