The correct option is B Seven
While it has been undertaken every 10 years, beginning in 1872 under british Viceroy Lord Mayo, the first complete census was taken in 1881. ... All the censuses since 1951 were conducted under the 1948 Census of India Act. The last census was held in 2011, whilst the next will be held in 2021. So by 2011 the total census were 7 census.