Options breakdown:

Option 1 suggests the decrease in food grain cultivation leads to high food inflation. While it`s plausible, the reduction in food grains cultivation does not automatically denote high inflation. There could be other factors at play, such as improvements in food import or advanced farming techniques.

Option 2 states that increasing incomes change consumption patterns. This may affect food inflation as people with higher income tend to consume more, possibly leading to increased demand and higher prices. However, this depends on many other socioeconomic factors.

Option 3 cites structural constraints in the food supply chain. This is a major contributor to food inflation as inefficiencies and bottlenecks can cause rise in costs, leading to inflation.

Based on the above, statements 2 and 3 (option 2) are regarded as the most reasonable causes of food inflation, thus, the correct answer. While statement 1 could partially contribute to inflation, it`s not a universally accepted cause without more specific context or data.