Questions26-30are based on the following chart : 　　Cigarette Smoking by Grade Level: 2005-2009
 
　　(说明：2005年为白框，2007年为灰框，2009年是黑框，扫描问题无法显示。)

The percentage of the 9th grade smokers in 2009 was （）

A．details about IOC’s emergency session
B．evidence against some IOC officials
C．ticket prices for men’s 100-meter final
D．pricing policy of the London Olympics

A．The 9th.
B．The 10th.
C．The 11th.
D．The 12th