Final answer:
The variation of Gibbs energy with pressure is linear, while the variation with temperature can be expressed in a logarithmic manner using natural logarithms, which makes option C) Linear, logarithmic the correct answer.
Step-by-step explanation:
The variation of Gibbs energy with pressure is generally a linear relationship, while the variation with temperature is more complex. An exponential relationship between vapor pressure and temperature (as indicated by your reference figures) can be represented linearly using natural logarithms, according to the Clausius-Clapeyron equation. In the context of ideal gases, Charles's law states that when pressure is constant, volume is directly proportional to temperature, indicating a linear relationship. Therefore, the correct answer is C) Linear, logarithmic, since Gibbs energy changes linearly with pressure and in a logarithmic manner with temperature when expressed using natural logarithms.