Which one of the following characteristics is associated with adsorption?
(a) $\Delta G$ and $\Delta H$ are negative buit $\Delta S$ is positive.
(b) $\Delta G$ and $\Delta S$ are negative but $\Delta H$ is positive.
(c) $\Delta G$ is negative but $\Delta H$ and $\Delta S$ are positive.
(d) $\Delta G, \Delta H$ and $\Delta S$ all are negative.