The piano is a great instrument because of how easy it is to pick up on it. Unlike other instruments like the violin, or the guitar, you always know what you are going to get when you attempt a note. It also sounds amazing to the ear and is very relaxing to the ear.
Its said to have an harmonious balance.
Maybe something like crystal I think, but out of yours I would pick karma!
Answer:
1) to emphasize how dangerously packed the streets are
2) to highlight the idea that Caesar suffers from illness
3) to suggest that Caesar will soon be put to death
