The relationship between the words in the question pair Virtual : Real is that of antonyms (opposites).
Looking at the options:
Genuine : Sanguine represents a relationship of opposites in classical behavioral traits (Authentic/Grounded vs. Impulsive/Hot-blooded/Overly Optimistic).
Atmosphere : Hydrosphere are complementary components of the Earth's ecosystem, not opposites.
Air : Oxygen is a part-to-whole relationship (Oxygen is a component of air).
Human : Homo sapien is a relationship of synonyms (Homo sapien is simply the scientific name for a human).
Since Option 1 is the only pair that establishes an opposing/contrasting relationship, it best matches the analogy.