The Secretary shall prescribe, as appropriate, written, oral, physical, foreign language, and other examinations for appointment to the Service (other than as a chief of mission or ambassador at large).

The Secretary shall ensure that the Board of Examiners for the Foreign Service annually offers the oral assessment examinations described in paragraph (1) in cities, chosen on a rotating basis, located in at least three different time zones across the United States.

Members of the Service serving under career appointments are career members of the Service. Members of the Service serving under limited appointments are either career candidates or noncareer members of the Service.

Chiefs of mission, ambassadors at large, and ministers serve at the pleasure of the President.

An appointment as a Foreign Service officer is a career appointment. Foreign Service employees serving as career candidates or career members of the Service shall not represent to the income tax authorities of the District of Columbia or any other State or locality that they are exempt from income taxation on the basis of holding a Presidential appointment subject to Senate confirmation or that they are exempt on the basis of serving in an appointment whose tenure is at the pleasure of the President.