8. What are the building blocks of blockchain technology that make it possible the use of cryptocurrency (e.g., BitCoin) as a means of payment?

a. An uncontrolled supply of cryptocurrency plus a decentralized database

b. Decentralized ledger, consensus mechanism, and a large amount of space to store all verified transactions

c. Decentralized ledger, proof-of-work, and a system of incentives for the network to verify transactions

d. All of the above