Lower oxidation state oxides are ionic. The highest oxidation number in the oxides, coincides with the group number and is attained in Sc2O3 to Mn2O7. The structure of V2O5 is more covalent than that of V2O3 and V2O4, which makes it more acidic. As a result, the basicity of V2O5 is greater than that of V2O4, which is in turn greater than that of V2O3.
Here in option C they have gien the increasing order of acidic character. So Option C is wrong.
V2O4 dissolves in acids to give VO2+ not in VO4−3 salts. So Option D is also wrong. Lower oxides are basic oxides and all chromium oxides other than CrO are amphoteric oxides.