Which Would Serve to Demonstrate the Workings of the Weber-Fechner

Which would serve to demonstrate the workings of the Weber-Fechner Relationship?

A) Cover one eye in dim light and then shine a light into the uncovered eye. Observe the pupillary reaction of the uncovered eye.
B) Testing for color blindness-whether one can discern among the different primary colors.
C) Testing hearing whether one can distinguish among different pitches or tones.
D) Without looking, another person places successively heavier weights, starting with a barely perceptible weight, on your outstretched hand to determine the sensitivity or the point at which a difference is perceived.
E) While looking, another person places successively heavier weights, starting with barely a perceptible weight, on your outstretched hand to determine the sensitivity or the point at which a difference is perceived.