Which one of the following characteristics is associated with adsorption?

Adsorption is spontaneous process, therefore change in the free energy ($\mathrm{\Delta }$G) for the process is negative.
According to Gibbs's Helmholtz eqn.
$\mathrm{\Delta }$G = $\mathrm{\Delta }$H-T$\mathrm{\Delta }$S
$\mathrm{\Delta }$S is negative because adhering of gas molecules to the surface lowers the randomness.
$\therefore$ $\mathrm{\Delta }$G can be -ve only when $\mathrm{\Delta }$H is -ve.