Which statement about the full court of the ICJ are correct?

A、NomemberoftheCourtshallparticipateinthedecisionofanycaseinwhichhehaspreviouslyactedasarepresentativeofoneoftheparties.;
B、Ajudge,whosenationalstateisapartyinacasebeforetheCourt,shallretaintherighttositinthatcase.;
C、Forapartywhichdoesnothaveajudgeofitsnationality,apersoncanbechosenbythepartytositinthecaseasanadhocjudge.;
D、Casesaredecidedbymajorityvoteofthefullcourt.