78. PTT is the most popular BBS site in Taiwan. In 2022, PTT announced that it stopped its TELNET service. Which one of the following is the main reason？ (A) Because TELNET does not support the compression feature which is mandatory for modern protocols. (B) Because TELNET requires more bandwidth than HTTP, PTT switches its service to websocket. (C) Because TELNET is a terminal-based service and cannot provide colorful view. (D) Because TELNET is an insecure connection way.