If (2, 1), (4, 5), (-1, - 3) are the mid points of the sides of a triangle, then the co-ordinates of its vertices are

• A. \[\left( -\text{3},-\text{7} \right),\text{ }\left( \text{17},\text{ 9} \right),\text{ }\left( \text{1},\text{1} \right)\]
• B. \[\left( -\text{3}.\text{ 7} \right),\text{ }\left( \text{7},\text{ 9} \right),\text{ }\left( -\text{ 1},\text{ 1} \right)\]
• C. \[\left( -\text{3},-\text{7} \right),\text{ }\left( \text{7},\text{ 9} \right),\text{ }\left( \text{1},\text{1} \right)\]
• D. none