Which type of population interaction is exhibited by 'mycorrhizae'?

The correct answer is Option (1) → Mutualism

Option (1) Mutualism — Correct. The fungus helps the plant absorb nutrients and the plant feeds the fungus.

NCERT Extract:
Population Interactions – “… (v) Mutualism: This interaction confers benefits on both the interacting species. Lichens represent an intimate mutualistic relationship between a fungus and photosynthesising algae or cyanobacteria. Similarly, the mycorrhizae are associations between fungi and the roots of higher plants. The fungi help the plant in the absorption of essential nutrients from the soil while the plant in turn provides the fungi with energy-yielding carbohydrates.”