How does a public IP address differ from a private IP address?

Public IP addresses are assigned to devices that need to be accessed over the internet. They are unique across the entire internet and are used to identify a device so that it can send and receive data. This means that any device with a public IP address can communicate directly with other devices on the internet without any additional routing or translation.

Private IP addresses, on the other hand, are used within local networks and are not routable on the internet. They allow devices on the same local network to communicate with one another, but they cannot be accessed directly from outside that network. This distinction is crucial for maintaining security and efficient use of IP addresses, as private addresses can be reused across different networks without conflict.

The option indicating that private IP addresses are always static does not hold true, as private IP addresses can be dynamic, depending on the network configuration. Similarly, the assertion that public IP addresses are used internally is misleading since they are primarily for external communication. Thus, the correct answer highlights the accessibility of public IP addresses over the internet, serving as a fundamental aspect of how internet communication is structured.