The number of bikes sold each year, in thousands, in a city since 2004 is shown by the graph below, where x represents the number of years since 2004. based on the graph, which of the following statements is true? a. the number of bikes sold decreased from 2004 to 2008 and increased from 2008 to 2014. b. the number of bikes sold increased from 2004 to 2006 and decreased from 2006 to 2014. c. the number of bikes sold decreased from 2004 to 2006 and increased from 2006 to 2014. d. the number of bikes sold increased from 2004 to 2008 and decreased from 2008 to 2014.