Darwins finches are an excellent example of

The correct option is B Adaptive radiation
Divergent evolution also known as adaptive radiation is the process whereby one species radiates out into different environments and as a result produces organisms that look different from each other, and may have many other differences.

Darwin found that the finches found on different islands of galapagos islands differ one another mainly in size and bill shape due to different feeding habit but were closely related to one another. They evolved from a common ancestral seed- eating ground finches and living in a geographical area of south american mainland. Hence, its an example of adaptive radiation.