A collection of nodes capable of environmental sensing, local computation, and communication with its peers or with other higher performance nodes

The correct answer is D. sensor network.

A sensor network is a collection of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, pressure, etc., and to cooperatively pass the data to a main location.

A voice portal is a computer system that can understand and respond to spoken commands.

A mobile portal is a website or application that is designed to be accessed on mobile devices, such

Geolocation is the process of determining the geographic location of an object, such as a person, vehicle, or device.