If Earth's crust became solid but water vapour was not available what would be the effect on hydrosphere?

Correct answer: Hydrosphere formation would be hindered due to lack of water source

Direct answer: Option A. A hydrosphere means all the water present on and around Earth, including oceans, lakes, rivers, groundwater and water vapour. For its formation, Earth needed a sufficiently cool, solid surface on which water could collect, and it also needed a source of water vapour. If water vapour were unavailable, cooling of the crust alone could not create oceans or a complete hydrosphere. Therefore option A is correct: the lack of a water source would hinder hydrosphere formation. Option B is wrong because a solid crust would not make the core melt. Option C is wrong because the existence of water vapour has no direct power to stop the solar wind. Option D is wrong because ozone formation requires suitable oxygen and sunlight; it would not automatically happen immediately merely because the crust became solid. The reasoning chain is: solid surface plus water source, followed by cooling and condensation, produces collected water. Remember: no vapour means no normal hydrosphere formation.