Explanation:

- e-NAM (Option 3): This is the correct answer. It stands for the National Agriculture Market. It's an electronic trading portal aimed at integrating the existing mandis for agricultural products in India. It seeks to create a unified national market for agricultural commodities.

- e-ANNA (Option 1): This does not relate to pan-India electronic trading for agricultural products and is not a known initiative in this context.

- e-BAZAAR (Option 2): While sounding like an electronic marketplace, it is not specifically aimed at integrating mandis in India for agriculture.

- e-KRISHI (Option 4): This is not recognized as a pan-India agrarian trading portal. It might relate to agriculture but not in the context of integrating mandis.