As `O_(2)` is cooled at 1 atm pressure, it freezes to form solid I at 54.5 K. At a lower temperature, solid I rearranges to solid II, which has different crystal structure. Thermal measurements show that for the phase transition solid I to solid II, `DeltaH=-743.1 J mol^(-1) and DeltaS=-17.0 JK^(-1) mol^(-1)`. At what temperature are solids I and II in equilibrium
A. 2.06 K
B. 31.5 K
C. 43.7 K
D. 53.4 K
