XYZ Growth Fund had the following total returns: 2005 18.90% 2006 27.20% 2007 79.50% 2008 -6.30% 2009 -25.30% What is the geometric mean return for the 5 year period? Select one: O a. 12.89% O b. 17.98% O c. 18.80% O d. 13.70%