Civil servants: Staff members who perform public duties in accordance with the law, are included in the national administrative establishment, and are paid by the state finances for wages and benefits. Which of the following are civil servants? ['Mr. Zhang is a university teacher and has worked in a college for 30 years.', 'Xiao Wang is a driver temporarily hired by the District Justice Bureau.', 'Sister Li has been a cleaner in the Personnel Department since she was laid off.', 'Mr. Chen became the Deputy Director of the Department of Transportation.']