Question

Which of the following represents an absolute threshold?

A guitar player knows that his D string has just gone out of tune.

A photographer can tell that the natural light available for a photograph has just slightly faded.

Your friend amazes you by correctly identifying unlabeled glasses of Coke and Pepsi.

A cook can just barely taste the salt she has added to her soup.

Your mom throws out the milk because she says the taste is "off".