Editor
The coordinates of mid points of sides of a triangle are (2,1), (-1,-3) and (4,5) then coordinates of its vertices are:
Difficulty: Easy
A: 
(1,2)(-1,-3)(5,4)
B: 
(6,7)(1,2)(-3,-7)
C: 
(1,1)(-5,4)(-1,-3)
D: 
(1,1)(7,9)(-3,-7)