The relative formula mass (M) of a Group 2 metal carbonate is 197 Relative atomic masses (Ar): C = 12
O = 16
Calculate the relative atomic mass (Ar) of the Group 2 metal in the metal carbonate
Name the Group 2 metal.

The relative atomic mass (Ar) : 137 and the element : Ba

The naming of chemical compounds is giving a special name to a compound that aims to facilitate the classification of compounds and facilitate the identification of a compound. The rules for naming chemical compounds have been determined by the IUPAC (International Union of Pure and Applied Chemistry)

This nomenclature includes the naming of ion compounds, covalent compounds, and polyatomic

The molar mass of a compound is given by the sum of the relative atomic mass of Ar  

M AxBy = (x.Ar A + y. Ar B)  

Group 2 metals have a +2 charge : M²⁺

So the compound of metal carbonate : MCO₃

Ar C = 12, O = 16

M MCO₃ = (1.Ar M + 1. Ar C+ 3. Ar O)  

The element with relative atomic masses 137 is Ba

So the compound : BaCO₃

it's all four options.