Test analysis: when the rubber rope reaches its original length, it begins to move with variable acceleration with gravity greater than elasticity and downward acceleration gradually decreasing; When gravity and elasticity are equal, the acceleration is zero and the speed is the maximum; After that, the gravity is less than the elastic force, and the acceleration gradually increases. When it reaches the lowest point, the acceleration is the largest and the speed is zero. In the process of movement, gravity and the elasticity of elastic rope do work, and the mechanical energy of the system composed of man and elastic rope is conserved; Suppose a person falls to the position where the rubber rope returns to its original length, the speed is V, the elastic force when falling to the lowest position is F, and the height of the rubber rope from returning to its original length to falling to the lowest position is H. Because the elastic force of the rubber rope changes linearly, the average elastic force of the rubber rope in this process can be obtained from the kinetic energy theorem, and then, according to Newton's second law, the acceleration when people reach the lowest position, so the correct option is C.