Stock X Stock Z Stock Y Realized Realized Realized Year End Return Return Return 2004 20.1% -14.6% 0.2% 2005 72.7% 4.3% -3.2% 2006 -25.7% -58.1% -27.0% 2007 56.9% 71.1% 279% 2008 6.7% 17.3% 2009 17.9% 0.9% -11.3% The covariance between Stock X's and Stock Y's returns is closest to: 0.12 0.10 0.69 0.69