the last question can't be H or G

Study the following phase diagram of Substance X. A B pressure (atm) E F G H temperature (K) O A OB If a sample of pure X is a mixture of liquid and gas, which point OC OD marks the highest possible temperature and pressure of the sample? OE OF OG OH O A OB Which is the liquid-gas coexistence curve? OC OD OE OF OG OH O A O B OC OD In what region would a sample of pure X be a gas? OE OF OG OH