Answer: The correct answer is Abraham Lincoln, Andrew Johnson, and Wiiliam Seward. Ulysses S.Grant was part of the initial plan,but had apparently left town before the incident and was not a target on April 14, 1865.
Explanation: Booth had three accomplices, Lewis Powell, David Herold, and George Atzerodt. Powell and Herold were to kill William Seward, and Atzerodt was to kill Vice President Andrew Johnson. Pwell was able to wound Seward with a knife, but Atzerodt got drunk and was unable to carry out his part.