The correct order for the acidic character of the following carboxylic acids is

V is most stable because its anion is stabilized to a greater extent through H–bonding with H atom of OH present on both ortho-positions; followed by II in which one OH group is present. Compound IV comes next to II because here –OCH3 group is present in ortho position which although is not capable of forming H–bonding yet more acidic than p- HOC6H4COOH (III) due to ortho effect. Compound III is less acidic than benzoic acid because of electron-releasing group in the para position. Thus