Step-by-step explanation:
The Van der Waals equation improves the ideal gas law by adding two different terms. The first one considers the molecular attraction and the second one considers the volume of the gas molecules.
The correction to the volume n*b depends on the size or volume of a molecule, and we can consider that the molecule will have a greater volume as the molar mass increases. So to solve our problem we have to look for the molar mass of each molecule.
molar mass of CO = 28 g/mol
molar mass of BF₃ = 68 g/mol
molar mass of He = 4 g/mol
molar mass of H₂O = 18 g/mol
molar mass of CO₂ = 44 g/mol
BF₃ has the largest molar mass so it is supposed to have the largest correction for the molecular volume.
Answer: BF₃