Explanation:

- Net National Income (Option 1): This represents the total income earned by a nation's residents and businesses, including any foreign income. It's not directly related to the nominal and real GDP ratio.

- Value Added GDP (Option 2): This measures the net output contributed by various production processes in an economy. It's not the ratio between nominal and real GDP.

- Green GDP (Option 3): Reflects economic growth while accounting for environmental costs. It doesn't describe the nominal to real GDP ratio.

- GDP Deflator (Option 4): This is indeed the ratio of nominal GDP to real GDP. It measures price level changes and inflation.