The correct answer is that Thomas Clarkson and William Wilberforce were known for working to end slavery in Britain, so choice B. Thomas Clarkson helped found The Society of Effecting the Abolition of Slave Trade and helped pass the trade act of 1807. He equally worked to end slavery in Great Britain, the United States and other parts of the world. William Wilberforce was also involved in the abolitionist movement, but was a politician first and foremost. However, after experiencing a Christian re-birth, he was very intrigued by morality, religion and education and helped to abolish slavery in Britain with The Slavery Abolition Act of 1833.