If be vertices of an equilateral triangle occurring in the anticlockwise sense, then 

a) 

b) 

c) 

d) 
None of these 
If be vertices of an equilateral triangle occurring in the anticlockwise sense, then 

a) 

b) 

c) 

d) 
None of these 
(c)
Let be an equilateral triangle such that the affixes of the vertices and are and respectively. Let the circumcentre of be at the origin. Then, and
Now,