What is Bitcoin?

Bitcoin is fundamentally a digital currency that enables peer-to-peer transactions without the need for intermediaries such as banks. This decentralized nature is one of its defining characteristics, as it operates on blockchain technology that records all transactions in a public ledger. Unlike traditional currencies, Bitcoin is not issued or regulated by a central authority, making it uniquely independent and resistant to government control. This framework allows users to send and receive payments directly with one another, facilitating a range of financial activities in a more accessible and often more cost-effective manner.

The other choices describe concepts that do not accurately represent Bitcoin's core functionalities. For example, Bitcoin is not a type of stock because stocks represent ownership in a company, whereas Bitcoin represents ownership of a digital currency used for transactions. Similarly, it does not operate as a centralized banking system; rather, it promotes a decentralized model. Lastly, while Bitcoin can be used within mobile payment applications, it is not itself a mobile payment app; instead, it functions as a form of currency that can be integrated into various platforms or services.