The oxoacids salts of group II elements from the given list are CaCO3,MgCO3 and Sr(NO3)2 as they all possess acid and base with oxygen atom. CaCO3 is a salt of H2CO3 and Ca(OH)2 MgCO3 is a salt of H2SO4 and Mg(OH)2 Sr(NO3)2 is a salt of HNO3 and Sr(OH)2