From left to right, the three regions of a phase diagram represent the of a substance.
a gas phase, liquid phase, and solid phase
b melting point, triple point, and boiling point
c melting point, boiling point, and sublimation point
d solid phase, liquid phase, and gas phase

D solid phase, liquid phase, and gas phase

Explanation: The phase diagram is  a graphical representation of the physical states of a substance under different conditions of temperature and pressure. The temperature is usually plotted on X axis and pressure is plotted on Y axis.

Thus as we increase the temperature and move from left to right the phase will change from solid and liquid as the kinetic energy of the molecules will increase and on further increasing the temperature, the liquid phase will change to gaseous phase as molecules will gain more kinetic energy on further increasing the temperature.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.

1 is the answer to this problem