The correct answer is option 3, 1921. The first Central Legislative Assembly was constituted in 1921. The Central Legislative Assembly was a legislative body introduced as part of the reforms implemented by the British government in India. It was created to provide representation for the Indian population and allow them to participate in the legislative process. The assembly consisted of members who were elected by various groups and communities, such as landlords, professionals, and business owners. The establishment of the Central Legislative Assembly was a significant step towards increasing Indian participation in the governance of the country.