Each side of a square is of length 4 units . The centre of the square is at ( 3 , 7 ) and one of its diagonals is parallel to y = x . Then co-ordinates of its vertices are
a. ( 1 , 5 ) , ( 1 , 9 ) , ( 8 , 9 ) , ( 5 , 5 )
b. ( 2 , 5 ) , ( 2 , 7 ) , ( 4 , 7 ) , ( 4 , 4 )
c. ( 2 , 5 ) , ( 2 , 6 ) , ( 3 , 5 ) , ( 3 , 6 )
d. ( 5 , 2 ) , ( 6 , 2 ) , ( 5 , 3 ) , ( 6 , 3 )