Instructions: 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 former Dragons' Den star and economic advisor to David Cameron and George Osborne was today charged with sexually abusing a 13-year-old. Technology millionaire Doug Richard, 57, who appeared in the BBC show in 2005 and famously failed to invest a penny in its second series, was arrested in January. The American-born businessman was today charged with three counts of sexual activity with a child and one count of causing or inciting a child to engage in sexual activity. Crown Prosecution Service lawyer Caroline Hughes said: 'We have concluded that there is sufficient evidence and it is in the public interest for Douglas Richard to be charged.Doug Richard has been charged with sexual offences against girl, 13Father-of-three, 57, was arrested in January and denies the allegationsRichard appeared in the first two series of the BBC show Dragons' DenHe has acted as an adviser to David Cameron and George OsborneMillionaire said today: 'I absolutely deny the charges against me and will contest this matter in court' 
 Question:The US-born businessman has worked closely with Mr _ over several years.
Output:
David Cameron