Option 1 -> The passage mentions the Bushveld Igneous Complex is a volcanic region, but volcanic ash is not mentioned as supporting microbial survival.
Option 2 -> The passage explicitly states "Clay deposits in the fractures may have provided nutrients" to support the microorganisms.
Option 3 -> The text clearly indicates microbes survive "far removed from sunlight, oxygen, and food sources," meaning oxygen is absent, not abundant.
Option 4 -> The passage specifies that these microbes exist in "extreme isolation, far removed from sunlight," making light unavailable.
Hence, Option 2: Nutrients from clay deposits in the fractures -> The researchers directly hypothesized that clay deposits within the rock fractures served as a nutrient source, enabling these primitive microorganisms to survive for billions of years in otherwise extreme conditions lacking oxygen and sunlight -> correct