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: The creator of the famous Leaf photograph, once believed to have been taken in the late 18th century, has been revealed - and it is not the world's oldest after all. It had previously been suggested that the picture had been taken by photography pioneers William Henry Fox Talbot or, even earlier, by Thomas Wedgwood. But now it has been revealed that a previously unknown woman, Sarah Anne Bright, from Bristol, captured the image 176 years ago. There was a media storm in 2008 when it was suggested that the red picture may not have been taken by Fox Talbot (1800 - 1877) in the 1830s as previously thought.Previous theories suggested picture could have dated back to the 1790sBut expert now believes it was taken by previously unknown Bristol womanThe image is 176 years old and was captured in 1839 by Sarah Anne Bright 
 Question:Although surviving letters show _ advised others on photography as early as the 1790s, none of his experiments have ever been located.

Thomas Wedgwood