Aerobic exercise: refers to the low-intensity, rhythmic, uninterrupted physical exercise that does not require high levels of athletic skills under the condition that the human body is fully supplied with oxygen. Which of the following is aerobic? ['Xiao Li has been insisting on weight lifting and throwing exercises in order to increase his arm strength.', 'Xiao Zhao, Xiao Su, Xiao Wu, Xiao Wu form a team to participate in the 4 × 100m relay race.', 'Xiao Wang practiced pole-vaulting after school in the afternoon to get good results in the sports meeting.', "Xiao Chen's body is slightly fat. In order to lose weight effectively, he briskly walks to the park for half an hour every morning."]