The correct option is A KHCO3 is soluble in water and NaHCO3 is sparingly soluble in water
KOH is preferably used to absorb CO2 to produce KHCO3+H2O
KOH+CO2→KHCO3+H2O
KOH is preferably used to absorb CO2 gas because KHCO3 whic is formed is soluble in water and NaHCO3 is sparingly soluble in water.
Hence, option A is correct.