The correct option is B Ca(HCO3)2
Lime water is aqueous solution of Ca(OH)2.
When CO2 is passed through lime water, it turns milky due to formation of CaCO3.
If excess of CO2 is added, precipitate of CaCO3 dissolve to form Ca(HCO3)2
Ca(OH)2(aq)+H2O(l)+2CO2(g)→Ca(HCO3)2(aq)