Please choose the correct answer to the question: Water used in a factory is heated to 75 degrees Celsius. It is discharged into a nearby river that has a normal temperature of 20 degrees Celsius. Which should most likely be done to minimize damage to the river?

Answer1: decrease the temperature of the factory water Answer2: increase the temperature of the river water Answer3: remove the vegetation from the river Answer4: add more fish to the river

Answer format: answer1/answer2/answer3/answer4