A drone equipped with a spotlight hovers directly above a point on level ground. The drone is rising vertically at 0.40 m/s and is currently 8 m above the ground. At the same instant, a 1.8-meter-tall runner is 6 m from the point on the ground beneath the drone and is moving directly away from that point at 1.2 m/s. At this moment, what is the rate of change (in m/s) of the length of the runner’s shadow on the ground?
a) 0.20
b) 0.35
c) 0.24
d) −0.24