which of these data sets is symmetrical?

A) 1,8,15,15,15,22,22,22,29,36,43
B) 1,8,15,22,22,22,29,29,29,36,43
C) 1,8,15,15,22,22,22,29,29,36,43
D) 1,1,15,15,22,22,22,29,29,36,43