The geometric mean of 6 observation was calculated as 13. It was later observed that one of the observation was recorded as 28 instead of 36. The correct geometric mean is
A. (9/7)¹/⁶
B. 3(9/7)¹/⁶
C. 13(9/7)¹/⁶
D. 13(9/7)¹/⁶