Kaun Banega Crorepati 16: Can you guess the answer for the Rs 50,00,000 question which contestant Sourav Chowdhury from Kolkata could not answer?

The recent episode of Kaun Banega Crorepati 16 began with rollover contestant Sourav Chowdhury from Kolkata, West Bengal. Sourav, a Senior Account Assistant at a CA firm, had already secured Rs 80,000 in the previous episode. Host Amitabh Bachchan kicked off the show by commending Sourav for his resilience in overcoming financial struggles and numerous challenges in life. Sourav shared that he aims to win enough money to secure his family's future and provide a home for his parents. The host resumes the game and asks the first question of the day for Rs 1,60,000. Chromium and which other elements are the main components of the alloy nichrome, used in heaters and toasters? He enabled the 'Dugnastraa' for the question. Sourav selects Option A) Nickel and wins the bonus amount. Sourav reveals he will use the entire bonus amount for his mother's health as she is facing few issues. Currently, she is being treated at a government hospital but he wants her to be treated at a private hospital.
Moving ahead, host Mr Bachchan presents the question for Rs 3,20,000. Which transnational river rises from the Chemayungdung Glacier near Manasarovar Lake? Sourav selects Option C) Brahmaputra and it is the correct answer. He wins the amount,
The host next plays 'Super Sandook' with Sourav and he manages to answer 5 questions correctly. He earns Rs 50,000 and revives his 'Audience Poll' lifeline. For the next question of Rs 6,40,000, he takes the help of 'Audience Poll' lifeline. What is the name of the Railway Protection Force initiative that secures and restores lost luggage of passengers? He selects Option D) Amanat.
Big B next presents the question for Rs 12,50,000. During the time of Iltumish, what were 'tanka' and 'jital' types of? He selects Option B) Coins and gets the amount. The host says that he knew that he would be able to answer the question as 'Tanka' means coins in Bengali.
Sourav gears up to answer the Rs 25,00,000 question. Who was the Union agriculture minister when the Green Revolution was initiated in India? As he is not aware of the answer, he takes the help of 'Video Call A Friend'. He selects Option A) Shri C Subramaniam on his friend's recommendation and wins the amount. Sourav gets a standing ovation from the studio audience.
He next faces the question for Rs 50,00,000. Which of these cricketers has served as the High Commissioner for India in Australia & New Zealand? As Sourav is not confident about the answer, he quits the show. Before leaving he takes a guess and selects Option B) Duleepsinhji and it was the right answer.
He quits the show and makes an exit, taking home Rs 25,00,000.