Hi
This particular question is from s block of inorganic chemistry from class 11 chemistry part 2 NCERT . The basic concept involved over here is that basicity of carbonates increases as we go down the group , because down the group the size of positive group 2 radical increases and basicity increases .
Do check out this link for IIT JEE preparation
https://engineering.careers360.com/articles/jee-main-preparation-tips
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile