<image>"Double Eleventh," referring to November 11th each year, represents a large shopping promotion carnival day initiated by e-commerce across China. In 2013, Taobao's sales on Double Eleventh reached 35 billion yuan. On November 12, 2015, the seventh Tmall Double 11 Global Shopping Festival concluded, with a full-day transaction volume of 91.217 billion yuan. Assuming the average annual growth rate from 2013 to 2015 is x, which of the following equations is correct (__)?
