An observer stands 150ft from the point directly below a hot-air balloon that is rising at a constant 10ft/s. Let θ be the angle between the observer’s line of sight to the balloon and the horizontal ground. Which statement best describes how θ and its rate of change behave as the balloon ascends?
a) θ increases, and dtdθ decreases over time.
b) θ increases, and dtdθ remains constant over time.
c) θ decreases, and dtdθ is negative.
d) θ increases, and dtdθ increases over time.