Concept:The boiling point of water depends on external pressure and the presence of dissolved solutes.
Explanation:At high altitude, atmospheric pressure is lower, so water boils at a lower temperature, not a higher one.
Dissolving a salt into water causes boiling point elevation, so the solution boils at a temperature above
100∘C.
Heating water in a sealed flask traps vapour and increases the pressure above the liquid, which raises the boiling point.
Increasing the rate of heat supply only makes the water boil faster; it does not change the boiling point itself.
Therefore, the correct actions are II and III.
Answer:C. II & III only.