Okay... the answer is
D.
The instantaneous speed of random movements of free electrons in copper (Fermi velocity) is about 1% of speed of light. However, the "net flow" of electrons (drift velocity) that makes up the electrical current is a few mm per second, assuming the amp output of about 1 ampere and a "usual" cross-section of speaker wire.
Then, the electromagnetic field (i.e., electrical "signal") transmits through copper at about 90% of speed of light. And this is why you "can't flip the light switch and jump into bed before it gets dark."
Of course, if you use the Kimbar Kable instead of the Home Depot lampcord, the Fermi velocity will magically increase at leaset 10 fold.
Oh, and don't forget that after a proper cable break-in, it will further increase by 2 fold because electrons can now travel more smoothly.
Seriously, the "pre-filled water hose" analogy is correct: when you open the spout at one end of a long hose, water starts to flow out at the other end of the hose IMMEDIATELY, even though the actual speed at which water flows inside the hose is fairly slow. In this case, the speed of water flow is equivalent to drift velocity of electrons, yet the "information" that the spout has been opened (pressure wave) transmits through the hose at the speed of sound.
