It'll certainly seem like it, because the water will get cold. But cold is not a thing. Heat is. What actually happens is that heat from the water flow into the ice (and melts it).
Your answer is C) The speed of sound is higher in solids than in liquids.
This contraption is a lot of fun, and you really should try it
some time.
The sound waves move from one can to the other one
by traveling through the string.
