Which situation results in a solution of zero?

A
The record low temperature in a city is −12
−
12
degrees. Today, the temperature is 12
12
degrees. What is the difference between the record low and today’s temperature?
B
Shawn earned $42
$
42
from babysitting last Friday night. On Saturday, Shawn earned another $42
$
42
from babysitting. How much money did Shawn earn from babysitting?
C
A building has 5 floors above ground and 5
5
floors below ground. An elevator descended 5
5
floors below ground. The elevator then rose 5
5
floors. How far was the elevator from the top floor?
D
Nicole walked 10
10
blocks north from her house to a friend’s house. After visiting, Nicole walked 10
10
blocks south back to her house. How far was Nicole from her starting place?

I really don't know how to awnser