You Find a Certain Share That Had Returns of 14

You find a certain share that had returns of 14 per cent,-27 per cent,19 per cent,and 21 per cent for four of the last five years.The average return of the share over this period was 9.5 per cent.What is the standard deviation of the share's returns?

A) 11.67 per cent
B) 12.90 per cent
C) 14.14 per cent
D) 18.47 per cent
E) 20.59 per cent