Option 1 suggests that only `Undernutrition` leads to malnutrition. Undernutrition, indeed, is a form of malnutrition resulting from lack of necessary nutrients due to insufficient food, but it`s not the only cause.

Option 2 adds `Imbalanced nutrition` alongside `Undernutrition`. Imbalanced nutrition, when the body`s nutrient intake is not proportionate, also leads to malnutrition. However, only including these two overlooks `Overnutrition`.

Option 3 includes `Overnutrition` and `Imbalanced nutrition`. Overnutrition, excessive intake of nutrients, indeed leads to malnutrition. But by excluding `Undernutrition`, it misses a significant factor.

Option 4 includes `Overnutrition`, `Undernutrition`, and `Imbalanced nutrition` - all of which are different ways an individual can become malnourished. Overnutrition results from consuming too much of a particular nutrient, often leading to obesity or specific nutrient overdoses. Undernutrition results from deficiencies due to a lack of general or specific nutrient intake. Imbalanced nutrition results from a disproportionate intake of nutrients. Hence, all three can lead to malnutrition, which makes option 4 the correct answer.