The feasibility of a chemical reaction can be explained based on DH, DS and DG, so an swer the following :

Answer

(A-q,t); (B-p,r); (C-r); (D-t)

Explanation

(a) `O_(2)` is more thermodynamically stable than `O_(3)`
(c) 0 mol `rarr 3` mol
(d) `0^(@)C` is the melting point of ice so ice so its melting is spontaneous at room temperature.