Consider the following climatic and geographical phenomena: 1. Condensation 2. High temperature and humidity 3. Orography 4. Vertical wind Thunder Cloud development is due to which of these phenomena?

All four phenomena are responsible for the development of thunder clouds (cumulonimbus). 1. Condensation: Essential for cloud formation. Water vapour condenses around hygroscopic nuclei to form water droplets and ice crystals that make up clouds. 2. High temperature and humidity: High temperature causes intense evaporation, providing abundant moisture. High humidity ensures sufficient water vapour is available for condensation when air is lifted. 3. Orography: Mountain barriers force moist air to rise. This orographic lifting cools the air and triggers condensation, contributing to the formation of thunder clouds especially in mountainous regions. 4. Vertical wind: Strong updrafts (vertical winds) are critical for thunder cloud development. They carry warm, moist air rapidly upward, enabling the cloud to grow vertically into a towering cumulonimbus, which produces thunder, lightning, and heavy rainfall. All four factors work together in the formation of thunder clouds, making (d) the correct answer.