The answer is falls. The quantity demanded falls. Hope this helps:)
I cannot do this entire thing for you, but I can help.
A cause is the thing that forces something else to happen. So, that could be anything. The effect is what comes after the event.
For example, the driver was texting while driving. That is the cause. He hit a girl. That is the event. He girl was injured. That is the effect.
Hope that helps!
Answer: I think it is
A. Let distant locations communicate quickly
Explanation: