New Delhi, June 13 : Former BCCI president Sourav Ganguly has said that the board was not ready for Virat Kohli to step down as India Test skipper, adding that it was his personal decision and the star batter can only reveal why he left the captaincy in the longest format of the game. Ganguly's latest remarks come in the wake of fans calling for the reinstatement of Kohli as India's Test captain after the Rohit Sharma-led side suffered a 209-run defeat to Australia in the World Test Championship final. However, Kohli hasn't been at his best with the bat in Test cricket in the last three years. "BCCI were not prepared for Virat Kohli leaving the Test captaincy. It was unexpected for us also after the South Africa tour. Only Virat Kohli can reveal why he left the captaincy. There is no point talking about this now because Virat Kohli left the Test captaincy. Selectors had to appoint an India captain. And Rohit was the best option at that time," Ganguly told Aaj Tak in an interview, after the WTC final. Kohli finished his tenure as the fourth-most successful captain in Test history, with 40 victories and 11 draws in 68 matches as the Indian captain. The 34-year-old is only behind Graeme Smith, Ricky Ponting and Steve Waugh on the list of captains with the most Test wins. /IANS