The correct answer is (c) 273 Kelvin.
Water has its maximum density at 4 degrees Celsius (39.2 degrees Fahrenheit) and 1 atmosphere of pressure. This is because the molecules of water are arranged in a more compact structure at this temperature and pressure. At higher temperatures, the molecules move faster and have more energy, which causes them to spread out and have a lower density. At lower temperatures, the molecules move more slowly and have less energy, which causes them to pack together more tightly and have a higher density.
(a) 373 Kelvin is the boiling point of water. At this temperature, the water molecules have enough energy to escape from the liquid state and enter the gas state. This causes the density of the water to decrease.
(b) 277 Kelvin is the melting point of ice. At this temperature, the water molecules have enough energy to break the bonds that hold them together in the solid state. This causes the density of the water to increase.
(d) 269 Kelvin is below the freezing point of water. At this temperature, the water molecules are moving too slowly to break the bonds that hold them together in the solid state. This causes the density of the water to decrease.