Social insurance: It is a system adopted by the state to distribute and redistribute national income through compulsory means to form a special consumption fund, and to provide workers with social assistance to protect their basic lives when they lose their ability to work or lose employment opportunities. Which of the following is social insurance? ['Work injury insurance.', 'Veterans Placement Fee.', 'State grants life relief to people in flood-stricken areas.', 'Passenger personal injury insurance.']