Causal prediction method refers to a prediction method that estimates the future results from the "context" of known causes based on the causal relationship of changes in the movement of things. Based on the above definitions, which of the following is the causal prediction method used in the following options? ["Xiao Ming's performance has always been among the best in the class, and he must be a good student with excellent academic performance.", 'Autumn crops have been harvested for three consecutive years. According to the comprehensive analysis of agricultural meteorological conditions in the previous stage, the average number of ears per mu, and the area of pests and diseases, this year should be a harvest year.', 'The river is clear and bottomed, indicating that there is no undercurrent in the river.', 'All athletes who have not won medals in this Olympic Games have not worked hard to train.']