The correct answer is (c) Urea.
Urea is a common fertilizer that is used to foliar apply to plants. It is a water-soluble nitrogen fertilizer that can be applied directly to the leaves of plants. Urea is a fast-acting fertilizer that can provide plants with a quick boost of nitrogen. It is also a relatively inexpensive fertilizer.
Sodium nitrate is a type of fertilizer that is not commonly used for foliar application. It is a water-soluble fertilizer that can be applied to the soil or to the leaves of plants. Sodium nitrate is a source of nitrogen and sodium. It is a relatively inexpensive fertilizer.
Ammonium chloride is a type of fertilizer that is not commonly used for foliar application. It is a water-soluble fertilizer that can be applied to the soil or to the leaves of plants. Ammonium chloride is a source of nitrogen and chlorine. It is a relatively inexpensive fertilizer.
D.A.P. is a type of fertilizer that is not commonly used for foliar application. It is a water-soluble fertilizer that can be applied to the soil or to the leaves of plants. D.A.P. is a source of nitrogen and phosphorus. It is a relatively expensive fertilizer.
In conclusion, the most popular fertilizer for foliar application is urea.