The correct answer is (b) William Bentinck.
William Bentinck was the Governor-General of India from 1828 to 1835. He is credited with taking the first important step towards financial decentralization in India by introducing the Indian Income Tax Act of 1835. This act introduced a system of direct taxation in India, which was a significant departure from the previous system of indirect taxation. The Indian Income Tax Act of 1835 was a landmark piece of legislation that had a profound impact on the financial system of India.
Lord Irwin was the Viceroy of India from 1926 to 1931. He is not credited with taking the first important step towards financial decentralization in India.
Lord Cornwallis was the Governor-General of India from 1786 to 1793. He is not credited with taking the first important step towards financial decentralization in India.
Lord Mayo was the Viceroy of India from 1869 to 1872. He is not credited with taking the first important step towards financial decentralization in India.