Answer : The correct options is, (1)

Step-by-step explanation:
(1)
:
This reaction shows sublimation process in which the phase changes from solid state to gaseous state at constant temperature.
(2)
:
This reaction shows evaporation process in which the phase changes from liquid state to gaseous state at constant temperature.
(3)
:
This reaction shows melting process in which the phase changes from solid state to liquid state at constant temperature.
(4)
:
This reaction shows freezing process in which the phase changes from liquid state to solid state at constant temperature.
Hence, from this we conclude that the option (1) equation represents sublimation process.