ANS:A - Chile salt petre

The natural inorganic fertilizer among the options provided is Chile saltpeter. Chile saltpeter, also known as sodium nitrate (NaNO3), is a naturally occurring mineral deposit found in the desert regions of Chile. It is mined from ancient deposits of dried lake beds and contains high concentrations of nitrogen in the form of nitrate. Oilcake and Gobar manure are examples of organic fertilizers:

• Oilcake: Oilcake, also known as oilseed cake or oilmeal, is a byproduct of oil extraction from seeds such as cottonseed, soybean, groundnut, etc. It is rich in nutrients like nitrogen, phosphorus, and potassium, making it a valuable organic fertilizer.
• Gobar manure: Gobar manure, also known as cow dung manure or cow dung compost, is organic fertilizer derived from decomposed cattle dung. It is a rich source of organic matter, nitrogen, phosphorus, and potassium, which help improve soil fertility and enhance plant growth.