What attack involves unauthorized access to data from a Bluetooth connection?

Bluesnarfing is the attack that involves unauthorized access to data from a Bluetooth connection. This method capitalizes on vulnerabilities in Bluetooth-enabled devices to access personal information, such as contacts, calendars, and sometimes even messages, without the user's consent. It typically occurs when devices are set to be discoverable and have weak security measures in place.

This technique contrasts with other options listed. For instance, bluejacking involves sending unsolicited messages to Bluetooth-enabled devices, which does not necessarily involve unauthorized access to data. Bluetooth hacking and Bluetooth sniffing are broader terms that refer to various methods of compromising Bluetooth security or eavesdropping on Bluetooth communications, but they do not specifically denote the act of unauthorized data access that bluesnarfing does. Thus, the precise nature of bluesnarfing as it specifically pertains to unauthorized data access makes it the correct answer.