Match the Column I of factors of modern synthetic theory/ speciation with the examples in Column II and select the correct option.

	Column I		Column II
A	Natural selection	I	Darwin's finches
B	Geographical isolation	II	Mule
C	Hybrid sterility	III	Cichlid fishes in Lake Victoria
D	Sympatric speciation	IV	Biston carbonaria

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.