Answer:
When charges are brought against the official for evidence of treason, bribery, or other serious crimes.
Step-by-step explanation:
Impeachment is the process of bringing charges against a person for misconduct. It is the process by which a federal official is called on trial for any act of misconduct, ranging from treason, bribe, or other serious crimes against the integrity and safety of the nation.
Though most impeachment cases occur to an official during his/her term in office, impeachment can also be done against a person who has already left office. Likewise, it can also be done against a person before he/she assumes office.
Thus, the correct answer is the fourth option.