All three elements mentioned in the question contribute to the warming of the atmosphere and therefore, the correct answer is option 4.

1. Soot: It absorbs sunlight and warms up the atmosphere. Soot particles can also become embedded in snow and ice, reducing their reflectivity and increasing melt rates.

2. Sulphur Hexafluoride: It is an extremely potent greenhouse gas. It is over 23,000 times more warming than carbon dioxide (CO2). Even in small amounts, Sulphur Hexafluoride contributes significantly to global warming.

3. Water vapour: It is the most abundant greenhouse gas in the atmosphere and plays a crucial role in Earth’s climate. It traps heat from the sun and contributes to the warming of the Earth`s surface.

Each option only partially acknowledges these contributors, whereas option 4 correctly includes all three.