28. A certain substance, X, has a triple-point temperature of 20°C at a pressure of 2.0 atm. Which one of the following statements cannot possibly be true? (A) X can exist as a liquid above 20°C. (B) X can exist as a solid above 20°C. (C) Liquid X can exist as a stable phase at 25°C, 1 atm. (D) Both liquid and solid X have the same vapor pressure at 20°C (E) All of these statements could be true