Step 1: Understanding the question.
This question asks about the state where cotton cultivation is most significant. Gujarat is a major cotton-producing state in India.
Step 2: Analyzing the options.
(A) तमिलनाडु: This is incorrect, as Tamil Nadu is not the leading state in cotton production.
(B) केरल: This is incorrect, as Kerala is not known for cotton production.
(C) गुजरात: Correct — Gujarat is a leading state in cotton cultivation in India.
(D) कर्नाटका: This is incorrect, as Karnataka does not lead in cotton production.
Step 3: Conclusion.
The correct answer is (C) गुजरात, as it is the leading state in cotton cultivation.