In U.S. history, a president has been impeached but none have ever been convicted. Key events like presidential death in office and resignation have occurred, while impeachment leading to conviction has not. Therefore, option 'b' is the correct answer. ;
In U.S. history, several presidents have died in office, resigned, and been impeached; however, none have ever been impeached and subsequently convicted. The correct answer to the question is option 'B', as this event has never occurred.
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