The Mid-Autumn Festival is a traditional festival in China. It's an occasion for family reunion. Chinese families like to get together to eat the moon cakes and watch the moon at the Mid-Autumn Festival night. There are some legends   of the Mid-Autumn Festival.  The Lady -- Chang E        In 2170 BC, the earth had ten suns circling over it, each taking its turn to brighten the earth. But one day all ten suns appeared together, making the earth too hot. The earth was saved by a hero called Hou Yi. He succeeded in shooting down nine of the suns. One day, Hou Yi stole the elixir of life   from a goddess. However his beautiful wife Chang E drank it and found herself floating to the moon. Hou Yi loved his wife so much that he didn't shoot down the moon. The Man -- Wu Gang        Wu Gang was a man who learned from his master. One day he asked if he could travel to some new and exciting place. The master was angry at Wu Gang's impatience  , and took him to the moon, telling him that he must cut down a huge cassia tree   before he could return to the earth. Though he  _ day and night, the magical tree restored itself with each blow, and thus he is up there chopping still. The cake -- moon cake      During the Yuan Dynasty China was ruled by the Mongolian people. Many people wanted to rebel   without being discovered. The leaders of the rebellion, knowing that the Mid-Autumn Festival was drawing near, ordered people to make special cakes. Inside each moon cake was a message with the outline of the attack. On the night of the Mid-Autumn Festival, the rebels successfully attacked and overthrew the government. What followed was the establishment   of the Ming Dynasty. Today, moon cakes are eaten for family reunion. What can we know about the Mid-Autumn Festival according to the passage?
The Mid-Autumn Festival has existed for a certain length of time. The Mid-Autumn Festival existed on the rebellion day. The Mid-Autumn Festival has existed since the Yuan Dynasty. The Mid-Autumn Festival has existed since the Ming Dynasty.