An elevator starts at the lobby and makes 4 stops. The positive numbers stand for going up, and the negative numbers stand for going down. Which expression gives the total number of floors traveled during the 4 stops?
A |9+−12+5+−8|
B |9|+|−12|+|5|+|−8|
C 9−12+5−8
D |(+9)+(−12)+(+5)+(−8)|
