【单选题】

You slip the key into the ignition and crank the engine to life.But before you put the car into gear, you tap a key on the keyboard mounted by the steering wheel, and your newest e-mail flashes up on the windscreen.

This seductive satyr is what you get when you cross a car and a computer.Dubbed the "network vehicle", or net-mobile, it may soon come to a driveway near you (probably the one belonging to your rich neighbor). In a net-mobile, a motorist could tap into a regional road system but also to map out a route around rush-hour traffic snags.Drivers and passengers will be able to send and receive e-mail, track the latest sports scores or stock quotes, surf the Web, and even play video games. Or so, at least, say a number of computer-industry firms such as Microsoft, Sun, IBM and Netscape.
The modern car is already an electronic showcase on wheels. On-board microcomputers improve fuel economy and reduce emissions. They operate anti-lock brake systems, and on some cars even regulate the firmness of the shock absorbers.But much of the technology needed to add extra is available now.A、prototype network vehicle, produced by a consortium of Netscape, Sun, IBM andDelco (an automotive-electronics firm based in Michigan), was introduced at the recent annual computer-industry show in Las Vegas.
It not only offered such desktop-computer-like services as e-mail, but allowed a driver to use them without looking away from the roaD、It was operated by voice commands and projected its data on to the windscreen, using the same sort of head-up display system found in modern fighter jets. Members of the consortium think a real-world network vehicle could be in production in as little as four years.
Car makers have already begun rolling out some of the features found on these prototype net- mobiles. If the driver of a General Motors car equipped with its On-Star system locks his key in the car, for example, an emergency centre can transmit a digital signal to unlock the doors. On-Star also calls automatically for help if an accident triggers the airbags. Toyota and General Motors are among a growing list of firms offering in-car navigation systems.And inEurope,BMW and Mercedes-Benz recently introduced navigation hardware that can not only plot out a route, but alert a driver to traffic jams.
The in-car navigation system has all of the following functions,EXCEPT ______.
A、call for help if an accident triggers the airbag
B、transmit a digital signal to unlock the doors
C、alert emergency centre if key is locked in the car
D、plot out route and alert one to traffic jams