Five years ago you decided to purchase Bubbly Corp. stock. The stock has had annual returns of -5 percent, 6 percent, 14 percent, 6 percent, and 4 percent for the past five years, respectively. What is the standard deviation of returns for this stock? Multiple Choice 7.07 percent O 7.34 percent O 6.37 percent 6.78 percent 6.07 percent