Seven-year-old sangram is not allowed to touch the tv remote. nevertheless, he uses the remote to change the volume from level 15 to 17. his parents, who are in the next room, seem unaware. the next day, sangram becomes bold and turns the volume from level 15 to 30. his father yells at him, "stop playing with the remote! " what prevented sangram's father from noticing the volume change on the previous day? a. difference threshold
b. fixed threshold
c. absolute threshold
d. distinct threshold