ANS:C - water

Out of the substances listed, one ton of water will store the maximum heat for a rise of 30°C in temperature. Water has a high specific heat capacity, which means it can absorb and store a large amount of heat energy compared to other substances. Specifically, water has a specific heat capacity of approximately 4.184 J/(g°C) or 4184 J/(kg°C), which is significantly higher than most other common substances. This property of water makes it an excellent heat reservoir. When one ton (1000 kg) of water is heated by 30°C, it will absorb and store a considerable amount of heat energy, which can then be released gradually as needed. This high heat capacity of water makes it useful in various industrial processes, heating systems, and as a coolant in many applications. In contrast, substances like steel, lignite (a type of coal), and limestone have lower specific heat capacities compared to water. Therefore, they would require either larger quantities or higher temperature changes to store the same amount of heat energy as one ton of water.