The growth of exports when India enters into Free Trade Agreements (FTAs) with other nations is influenced by multiple factors. Based on the search results, all the factors listed in the options play a role in determining export growth: 1. Extent of tariff reduction vis-à-vis MFN tariffs: Tariff reductions are a key component of FTAs and can significantly enhance export growth by making goods more competitive in partner markets. 2. Extent of relaxation in terms of rules of origin: Rules of origin can either facilitate or hinder trade depending on their stringency. Relaxation in these rules can lead to increased utilization of FTAs and thus boost exports. 3. Extent of relaxation in sanitary and phytosanitary measures: These measures can act as trade barriers. Relaxation or harmonization of such measures can facilitate smoother trade flows, especially in agricultural products. 4. Level of infrastructure in India: Good infrastructure is crucial for efficient trade logistics, reducing costs, and improving competitiveness, thereby supporting export growth. 5. Income in nations with which India enters into FTAs: Higher income levels in partner countries can lead to increased demand for imports, including those from India, thus supporting export growth. Therefore, all the factors (1, 2, 3, 4, and 5) are relevant, making option 4 the correct choice.