Darwin's finches are the example of:

The correct answer is Option (4) → Adaptive radiation

Option (4) Adaptive radiation — Correct. Darwin found many kinds of finches on the Galapagos Islands, each with a beak suited to its food, all evolved from one seed-eating ancestor. Evolution of different species from one point, spreading into different habitats, is adaptive radiation.

Note: A similar question was also asked in CUET (UG) 2025 on 29-05-2025 (Slot 1).

NCERT Extract:
What Is Adaptive Radiation? – “… From the original seed-eating features, many other forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches (Figure 6.5). This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. Darwin’s finches represent one of the best examples of this phenomenon. Another example is Australian marsupials. A number of marsupials, each different from the other (Figure 6.6) evolved from an ancestral stock, but all within the Australian island continent.”