Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct  answer to each of the questions from 46 to 50

In 2007, at a heavily hyped press event in San Francisco. Apple co-founder Steve Jobs stood on stage and unveiled a revolutionary product that not only broke the mold but also set an entirely new paradigm for computer-based phones. The look, interface and core functionality of nearly every smartphone to come along since is, in some form or another, derived from the original iPhone's innovative touchscreen-centric design. Among some of the ground-breaking features was an expansive and responsive display from which to check email, stream video, play audio, and browse the internet with a mobile browser that loaded full websites, much like what is experienced on personal computers. Apple's unique iOS operating system allowed for a wide range of intuitive gesture-based commands and eventually, a rapidly growing warehouse of downloadable third-party applications. 

Most importantly, the iPhone reoriented people's relationship with smartphones. Up to, then, they were generally geared toward businesspeople and enthusiasts who saw them as an invaluable tool for staying organized, corresponding over email, and boosting their productivity. Apple's version took it to a whole other level as a full-blown multimedia powerhouse, enabling users to play games, watch movies, chat, share content, and stay connected to all the possibilities that we are all still constantly rediscovering. 

What is the passage mainly about? 

• A. 
  Press event in San Francisco
• B. 
  Apple's iPhone
• C. 
  Apple's unique iOS operating system
• D. 
  Apple co-founder Steve Jobs