Altruistic behavior: refers to the behavior of people to help others out of their own volition, without expecting any compensation. Which of the following is altruistic? ["Xiao Zhang rescued the child who fell into the water Yu, and later hoped that Yu's family would pay him.", 'Xiao Li subdued the gangster who tried to rob. Afterward, the unit rewarded him with 5000 yuan.', 'Li Xiaoli, a soldier, ten years as a day.', 'Ding found a fire in his home, quickly dialed 119, and assisted firefighters in fighting the fire.']