None of those. Those are just a form of "storing" money.
Money is the value that somebody is willing to give in exchange for a product or service.

Also you can say that money is energy. Especially when you refer to Bitcoin.

Bitcoin is ENERGY stored in the most secured and brilliant way.

What people do every day, every minute? People are always in a continuous run for gathering energy, in many different forms: to eat, to store, to trade, to use it as money, to use it as savings. People depend 100% of energy. People are spending also large amounts of resources just for STORING energy.

And then Bitcoin comes and fix all of these problems: Bitcoin is pure storage for energy, secured by mathematical algorithms, something that will be eternal. If you own Bitcoin YOU OWN ENERGY FOR THE REST OF YOUR LIFE.

DarthCoin

runningruffalo

bitcoin

1) numbers displayed on screens (digital wallets) 
2) printed pieces of paper
3) chips embedded into plastic cards
4) crypto coins in virtual wallets
5) metal coins 