Which device is M2M (machine to machine)?

The correct choice highlights a temperature sensor connected to a fire suppression system as an example of machine to machine (M2M) communication. M2M refers to the direct communication between devices without human intervention, enabling automated systems to monitor and react to specific conditions.

In this case, the temperature sensor continuously monitors temperature levels and can autonomously trigger the fire suppression system if it detects a fire risk. This scenario encapsulates the essence of M2M: devices exchanging information and actions based on set parameters to enhance safety and efficiency.

Other options, while connected to the internet or involved in communication, often require human involvement or are more oriented towards consumer interaction rather than automated machine communication. For instance, an internet-connected TV requires user input for viewing content, and a home alarm that dials the police needs a human to initiate the alert after detection. Similarly, a car GPS primarily helps with navigation for human drivers instead of functioning independently in a machine-to-machine context.