Given the question: When Steven was a young boy, he moved quite often with his family and so he never had many friends. He spent a lot of time on his own and liked to play with electronic things. Steven had a neighbour, Steve Wozniak. Steve was a little bit younger than Steven but also liked to play with electronic things. Steven made a microphone and Steve asked him many questions about it until he understood how it worked. Steven liked the fact that such a young boy was also interest ed in electronic things and so he taught him everything he knew. When they were a little older and knew more about electronic things, they made a "blue box". People could make free phone calls by breaking into the phone company's system with this box. They sold this to many people even though it was illegal , but this is not why they are famous today. Steven and Steve were the inventors of the first PC--personal computer. They called their first computer the Apple I. They invented it only for fun and to make themselves known among their friends. They did not think it would become so popular. They just liked playing computer games on it. Their computer made it cheaper and easier for people to own and use a computer. Their PCs were so popular that they made a new PC called the Apple II. Soon many schools, families and factories were using their computers. Without the two clever men, the personal computers might never have appeared. What did the "blue box" do? A) People could play computer games with it. B) It helped people make electronic things. C) It paid for everybody's telephone calls. D) It helped people make free phone calls.
The answer is:
D