You decided to purchase Renfrow Corp. stock five years ago. The stock has had annual returns of $-6$ percent, $9$ percent, $7$ percent, $-3$ percent, and $6$ percent for the past five years, respectively. What is the standard deviation of returns for this stock?

Multiple Choice

$5\mathrm{.}95$ percent

$6\mathrm{.}41$ percent

$5\mathrm{.}89$ percent