History: How does overall amplitude impact our sense of volume over frequency?

How does overall amplitude impact our sense of volume over frequency?

• More variation at higher amplitude, less variation at lower amplitude.
  The opposite is true.
• Less variation at higher amplitude, more variation at lower amplitude.
  Correct!
• There is no correlation between amplitude and our sense of volume over frequency.
  There is a correlation.
• None of the other answers.
  One of the answers is a good option.