Select the text in the passage.
Which sentence contains an inappropriate shift in voice?
Nelson Mandela's Presidency and Retirement

1 As the president of South Africa, Nelson Mandela worked tirelessly to bring unity to his country. He supported the all-white national rugby team as a way to establish positive relations between whites and blacks. In 1996, Mandela signed a new constitution into law. 2 The new constitution gave power to the central government and guaranteed the rights of minorities and the freedom of expression.
In 1999, Mandela retired from politics. 3 The Mandela Foundation was founded by him, and he raised money to build schools and clinics in rural South Africa. Mandela also published several books including No Easy Walk to Freedom and Nelson Mandela: The Struggle Is My Life. In 2004, at the age of 85, Mandela moved back to his childhood village of Qunu. 4 For the most part, he remained out of the public eye after he returned to his boyhood home.