Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: A Chinese mother who never gave up hope of finding her beloved son cried tears of joy as she was finally reunited with him - 26 years after child traffickers snatched the four-year-old from the street. Lan Mingxi's son Li Wei vanished in September 1989, taken from the street by two strangers who no one ever saw again. His disappearance left Mingxi distraught, and over the years she did all she could to find her little boy, writing nearly 10,000 letters and appearing on television countless times, always holding the only photo she had of Wei, taken when he was three years old.Lan Mingxi was reunited with her son Li Wei after decades of heartacheWrote 10,000 letters and appeared on TV numerous times trying to find himOnce pretended to be a businesswoman to enter a child traffickers houseAfter her daughter was diagnosed with leukaemia, she decided to try againShowed picture of Wei aged three - and one of his friends recognised itDNA tests proved it was Wei, who had no idea he had been snatched 
 Question:Luck: The picture was seen by one of _'s friends, who thought they could be the same person.

Li Wei