Keegan Notices That His Favorite 55-Cent Candy Bar Seems Lighter

Keegan notices that his favorite 55-cent candy bar seems lighter than usual and so he checks the label to find that it is lighter by 10 g than it used to be.He decides to buy a larger candy bar instead and doesn't notice that the 99-cent candy bar is also 10 g lighter.Keegan's behaviour illustrates the fact that

A) the just noticeable difference is not a reliable measure of psychophysiological judgment.
B) sensory adaptation may occur in the short time between holding one candy bar and then the other.
C) difference thresholds are unpredictable because sometimes he can and sometimes he can't detect a 10 g change.
D) the larger a weight is,the greater the change must be before one can detect a difference.