A person 2 meters tall walks directly away from a streetlight that is 8 meters above the ground. If the person is walking at a constant rate and the person's shadow is lengthening at the rate of 4/9 meters per second, at what rate, in meters per second, is the person walking? Select one: O a. 4/27 O b. 4/9 O c. 3/4 O d. 4/3 O e. 16/9