You Probably Can Detect a Weight Difference Between a 1-Ounce

Multiple Choice

You probably can detect a weight difference between a 1-ounce and a 2-ounce envelope.But if you pick up a 20-pound package,you'd probably need another package that weighs at least 20.5 pounds before detecting a difference between them.This description illustrates:

A) Weber's law.
B) signal detection theory.
C) absolute thresholds.
D) perceptual constancy.