According to Weber's Law 2 onions should be added to notice the difference.
The correct option is b. 2
Step-by-step explanation:
Weber’s law deals with hypotheses in psychophysics. The law explains the relation between the actual change in a physical stimulus and the perceived change.
Weber’s law was proposed by a German philosopher Gustav Theodor Fechner. Fechner dealt with psychophysics and explains about human perception.
Regarding the question, if one onion is to be added to the pot of chili to notice the difference, then two onions will be required to add to notice the difference while making twice as much chili with 10 onions.