Option B is the correct answer. Leon is correct.
Leon and Sara are arguing over when the best time is to de-grease soup. Leon says that its easiest to de-grease soup when boiling. Sara says its easiest to de-grease soup when it is cold. So in this scenario, Leon is Correct.
When soup starts to boil, a layer of grease is formed over the soup surface. At this time it is the easiest to remove this layer with a spoon. This layer can be formed two to three times while boiling. Each time the layer can be removed. In this way, all the grease is removed.