Option 1 states that only infrared radiation is used to cook food. Infrared radiation is a form of electromagnetic radiation that has longer wavelengths than visible light. It is commonly used in cooking appliances such as grills and ovens to generate heat and cook food. However, this option is incorrect because there is another type of electromagnetic radiation that is also used for cooking food.

Option 2 states that only microwave radiation is used to cook food. Microwave radiation is a form of electromagnetic radiation that has shorter wavelengths than radio waves. It is commonly used in microwave ovens to heat and cook food. This option is incorrect because there is another type of electromagnetic radiation that is also used for cooking food.

Option 3 states that both infrared and microwave radiations are used to cook food. This is the correct answer. Infrared radiation and microwave radiation are both used in various cooking appliances for different purposes. Infrared radiation is used for direct heating and grilling while microwave radiation is used for quick and efficient heating.

Option 4 states that all electromagnetic radiations are used to cook food. This is incorrect because not all types of electromagnetic radiation are used for cooking food. Only specific types, such as infrared and microwave radiation, are commonly used.