Intensive subsistence farming is prevalent in densely populated regions, notably in nations such as India and China.
Statement I: Correct. High population density leads to very small land holdings.
Statement II: Correct. A defining feature is the limited use of machinery and a strong reliance on manual labor.
Statement III: Incorrect. It is primarily practiced in South and Southeast Asia, not extensively in Central Asia.
Statement IV: Correct. While yields per unit area are high, productivity per laborer is low due to significant dependence on manual work.
So, the correct answer is (A): Statements I, II, and IV are correct.