The angle measures associated with which set of ordered pairs share the same reference angle?
a. (- √3/2 ,- 1/2 ),(- 1/2 ,- √3/2 )
b. ( 1/2 ,- √3/2 )· (- √3/2 , 1/2 )
c. (- 1/2 ,- √3/2 ),( 1/2 , √3/2 )
d. ( √3/2 , 1/2 ),( 1/2 , √3/2 )