Answer:
D) when the air around it is very cold and dry
Explanation:
Sublimation is a process which involves a phase change from solid directly to the vapor, bypassing the liquid phase.
Based on the phase diagram of water, sublimation is favored under conditions of low temperature and pressure i.e. when the air around it is very cold and dry.
Therefore, options A), B) and C) are incorrect as they will only melt ice into a liquid.