Q:Read the article and select the best answer. Article: The next generation of smart phone could combine the date from its gyroscopes with a built-in compass to allow you to track your indoor movements even without GPS. Research described it in the international Journal of Innovative Computing and Applications by Shahid Ayub of Lancaster University, and his colleagues there and at HW Communications, suggests that the embedded inertial sensors in many smart phones have added the facility to be used for localization and tracking applications. The primary benefit of using smart phones is that no additional infrastructure would need to be installed for monitoring personnel movements in a wide variety of situations not least staff, equipment and inventory movements in warehouse facilities, shopping malls and factories. In contrast, other technology being proposed would require new equipment,such as RFID technologies. However, smart phones do not yet have the ability to pinpoint their location without recourse to the GPS system, which is not accessible indoors and has the added disadvantage of using up battery power very quickly even if it could be used. Inertial navigation only provides the necessary information to a specified starting point the team says. This is useful for anyone with a non-GPS smart phone who wishes to track the route they take when walking or jogging if they specify their starting point. The team suggests that pedestrians indoors could be positioned using a combination of the smart phone accelerometer and an built-in digital compass, something that will become available in future smart phones. They have now investigated the potential of three different smart phone placement modes: idle, hand held and listening, which could be used with pedestrian dead reckoning (PDR) techniques to allow users to record the path they follow or for various kinds of workplace or other monitoring requirements. "The technique could be used in underground tube stations, airports , train stations where there is no infrastructure installed for tracking or... Question: We can learn from the passage that the recent studies of smart phones _ . Options: A: were conducted by Shahid Ayub alone B: were supported by GPS C: have no connection with everyday needs D: can be applied to underground tube stations
A:
D