You can increase the vapor pressure of a liquid by:
increasing the viscosity.
establishing dynamic equilibrium.
increasing temperature.
using a nonvolatile compound.
all of the above

Option (c) is the correct answer.

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

When we increase the temperature of a liquid substance then there will occur an increase kinetic energy of the molecules. As a result, they will move readily from one place to another.

Hence, liquid state of a substance will change into vapor state of the substance. This means that an increase in temperature will lead to an increase in vapor pressure of the substance.

Thus, we can conclude that you can increase the vapor pressure of a liquid by increasing temperature.

i think the answer is a, hope this is right, that would be my best guess.