Please answer the following question: Read the following article and select the best answer. Article: Researchers around the world have been trying their hand at making better use of the huge amount of wind energy available in nature to produce clean energy. Apart from this, studies are being carried out to harness usable wind energy produced by man-made technologies. One useful source identified by Indian inventor Santosh Pradhan about two years ago is a speeding train, which produces fierce wind that can be transformed into electricity. According to Pradhan's proposal, with a few small improvements in existing trains running in Mumbai, the largest city in India, at least 10,000 megawatts of electricity could be harvested each day. Building on this principle, designers Ale Leonetti Luparinia and Qian Jiang from Yanko Design have created a device called T-Box that harnesses wind energy from speeding trains. T-Box can be placed within the railway tracks. It is half-buried underground between the concrete sleepers , which does not disturb the normal train operating at all. According to Yanko, around 150 T-Boxes can be fitted along a 1,000-meter railway track. A train running at a speed of 200 kph can produce winds blowing at 15 miles a second. Based on this calculation, 150 T-Boxes can produce 2.6 KWH of electricity per day. The T-Box's design won a silver medal in last year's Lite-On Awards and was exhibited last summer at the Xue Xue Institute in Taipei, Taiwan Province. Though the figures look impressive, it is important to remember that the design is still at a conceptual stage and hasn't taken into account issues such as pieces of waste material produced by the device and the efforts and costs involved in the maintenance of the device. We can expect the technology to see the light of the day only after it clears these issues. If so, rail travel, one of the greenest forms of travel, will become greener and more energy-efficient. Question: The passage is mainly written to _ . - encourage more people to travel by train - explain the advantages of electricity - tell readers how to save energy and money - introduce a new invention to readers
Answer:
introduce a new invention to readers