Please answer the following question: Read the article and select the best answer. Article: It is commonly known that Japan went from a 19th century national economy to a 20th century global economy in a time span of 30 years between 1945 and 1975. What is less known is that Japan, understanding that fast, efficient transport was the key to a global economy, was the first country in the world to introduce the "Bullet Train". Kawasaki Heavy Industries was duly appointed the manufacturer and the first high speed train went "on line" in 1964. The Shinkansen, as is known in Japan, made its first journey between her capital and Osaka, a distance of 301 miles, at a speed of 132 mph. The next country to introduce high speed trains was France. SNGF, the public rail system in France, was losing passengers to other forms of transport and introduced the "TGV" (Train a Grande Vitesse) to counteract the trend in 1981. As a result of Opec controlling the oil market in 1974, the train was designed to be powered by gas turbines. It ran on a specially built track between Lyon and Paris. Eight years later another TGV was introduced, this time between the coast and Paris. Soon, France became the most rail efficient country in the world with high speed train connections to Belgium, London, Germany, Switzerland, Spain and the Netherlands. There was another positive element that resulted from the introduction of high speed trains. Between 1964 and 1991, Japan's Shinkansen had transported in excess of three billion passengers without there being a single fatal accident and eleven years after France introduced the TGV, it still had a 100% safety record. This statistic has never been equaled by the traditional slow moving trains in any country. China has become the fourth country to produce such trains, after France, Germany and Japan. China's first domestically produced bullet train with a maximum speed of 350 kilometers per hour has rolled off the production line. Equipped with highly-efficient power system, the currently fastest train in China is also energy efficient. When the train is running, it can transfer kinetic... Question: What is the main idea of this passage? Options: A: Bullet trains are the most convenient means of transportation compared with others. B: Bullet trains are the only key to developing the economy of a country. C: Bullet trains can save time and energy for people. D: Bullet trains have many advantages and are accepted by more and more countries.
Answer:
D