The correct answer is: a) 1872.
The first decennial census in Odisha was conducted in 1872. It was conducted by the British government. The census was used to collect data on the population, religion, caste, education, and occupation of the people of Odisha. The census was also used to collect data on the land, agriculture, and industries of Odisha.
The census was conducted by a team of British officials and Indian assistants. The census was conducted in two phases. The first phase was the enumeration phase, in which the population was enumerated. The second phase was the data processing phase, in which the data collected in the enumeration phase was processed and analyzed.
The census was a major undertaking and it took several years to complete. The census was a valuable source of information on the people and economy of Odisha. The census was used to develop policies and programs for the development of Odisha.
The other options are incorrect because they are not the years in which the first decennial census in Odisha was conducted.