Which one of the following statements is incorrect about the different generations of mobile communications?

• A. Only one subscriber at any given time is assigned a channel in the first generation (1G).
• B. In second generation (2G) mobile communication, 5 MHz multi-carrier system is used.
• C. For third generation (3G) voice call and data is an important feature.
• D. Global roaming across multiple networks and multimedia is provided to users anytime and anywhere at a much higher speed in Fourth generation (4G) mobile communication.