The correct option is B Mahanagar Telephone Nigam Limited
In 1986, Videsh Sanchar Nigam Limited (VSNL) took a big leap in the field of service providing. Before that, Mahanagar Telephone Nigam Limited (MTNL), a public sector company for giving telephone service in big cities. In the 1990s, Videsh Sanchar Nigam Limited held the distinction of being the main internet service provider in India.