A state function is a property whose value does not depend on the path taken to reach that specific value, but only on the current state of the system. (I) According to the first law of thermodynamics, $\Delta U = q + W$. Internal energy ($U$) is a state function . (II) Heat ($q$) is a path function because its value depends on the path taken . (III) Work ($W$) is also a path function . (IV) The expression $H - TS$ represents the Gibbs free energy ($G$), which is a state function ($G = H - TS$) . Therefore, heat ($q$) and work ($W$) are not state functions.