Which of the following reactions is spontaneous only at relatively low temperature?

The reaction given in option B,

${\mathrm{NH}}_3\left(g\right)+\mathrm{HCl}\left(g\right)⟶{\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{s}\right)+176\mathrm{kJ}$

In this reaction entropy change is less than zero.

$-T\mathrm{\Delta }S$ becomes +ve

Therefore,

In, $\mathrm{\Delta }S<0,$ so $,-T\mathrm{\Delta }S$ becomes +ve.