Between the following options the only one that is not released during a volcano eruption is cold water (b), since all the others alternativies are released during a volcano eruption. During volcano eruptions there is the release of gas molecules (H20, CO2, SO2, CO, and other small amounts of other gas species), in the beginning of the eruption dissolved magma, molten rocks, and lava are commonly see, since it is related to the structure of the volcano and the high temperature that happen during the event of activity of that structure.