The correct answer is: a) Rock phosphate.
Rock phosphate is a mineral that is crucial in the fertilizer industry. It is a major source of phosphorus, which is an essential nutrient for plant growth. Phosphorus is used in the production of many different types of fertilizers, including ammonium phosphate, diammonium phosphate, and triple superphosphate. These fertilizers are used to help plants grow strong and healthy.
Gypsum is a mineral that is used in a variety of industries, including the construction industry, the paper industry, and the fertilizer industry. Gypsum is used in the fertilizer industry to help regulate the pH of the soil. It is also used to help improve the drainage of the soil.
Nitrates are a type of salt that is found in nature. Nitrates are used in the fertilizer industry to help plants grow. Nitrates are also used in the production of explosives and gunpowder.
Potash is a mineral that is found in nature. Potash is used in the fertilizer industry to help plants grow. Potash is also used in the production of glass, soap, and detergent.
In conclusion, rock phosphate is the mineral that is crucial in the fertilizer industry. It is a major source of phosphorus, which is an essential nutrient for plant growth.