Which of the following acids has the smallest dissociation constant?

Charge dispersal stabilizes and charge intensification destabilizes.(i) The inductive effect decreases with increase in distance of halogen atom from the carboxylate ion and hence the strength of acid proportionally decreases due to decrease in stability of carboxylate ion.(ii) The acidity increases with the increase in electronegativity of the halogen present due to −I effect of stronger electronegative group.Smallest dissociation constant means weakest acid, which is BrCH2CH2COOH because here Br (less electronegative than F) is two carbon atoms away from -COOH.