What is the main advantage of using a VPN for data transmission?

The primary advantage of using a VPN (Virtual Private Network) for data transmission is data encryption. When you use a VPN, your internet traffic is routed through a secure tunnel, which encrypts the data being transmitted between your device and the VPN server. This encryption protects the data from being intercepted by third parties, such as hackers or unauthorized entities, ensuring that sensitive information like passwords, financial details, and personal communications remain private and secure.

While the other options may have some truth in different contexts, they do not primarily define the core function of a VPN. For instance, increased speed is not guaranteed and often varies based on the server's location and load. Extended coverage can also depend on the VPN service provider and their server locations rather than being an inherent advantage. Reduced costs may occur with certain VPN services but is not a fundamental feature of how VPNs operate. Therefore, data encryption stands out as the main benefit due to its critical role in enhancing security during data transmission.