Which of the following examples is the best example of a physical stimulus that is likely to produce the just noticeable difference (jnd)?
a) you are holding a 5 pound bag of flour and 2 pounds of flour is added to it.
b) you are listening to a radio at level 4 volume, and someone turns it up to level 6.
c) you lift a 100 pound child onto a ride; then you lift a 102 pound child onto the ride.
d) you watch a traffic signal light turn from green to yellow.
e) you are carrying a bag of groceries and someone adds a loaf of bread to the top.