Matteo Misses His Grandpa Since He Passed Away

Multiple Choice

Matteo misses his grandpa since he passed away.He has his grandpa's old hat and he often smells it to remember him.He notices,however,that the smell quickly fades each time he does it,but it is back again the next time he tries it.What is the best explanation for Matteo's inability to smell his grandpa's scent after a few minutes?

A) it is below his just noticeable difference threshold
B) perceptual set
C) sensory adaptation
D) bottom-up processing