Please answer the following question: I'm taking a test and have to guess the right answer to the question after the article. Article: George Stephenson was born in 1781 in a poor family. He had to start work when he was only eight.When George was fourteen, he became his father's helper.He spent a lot of time learning about engines .And on holidays he often made one engine to pieces and studied each piece carefully.Soon he became a very good worker though he could not read or write.He began to learn English letters when he was seventeen years old.Every day after he did twelve hours of hard work, he walked a long way to have lessons from a young school teacher. On his eighteenth birthday,he wrote his own name for the first time in his life.George invented many things in his life.The train was the greatest one among them.Today when we take trains from one place to another,we'll think of this great man---George Stephenson. Question: From the passage we know George Stephenson was one of the greatest _ in the world. Options: A: workers B: writers C: learners D: inventors
Answer:
D