Answer:
D
Step-by-step explanation:
When you have two opposite numbers on a numberline, that is, a digit that has a negative value and the same digit having a positive value, when you add them together, we would have 0.
i.e. -a + b = 0
In the above options given, the numberline that shows this particular case is the numberline in option D.
In option D numberline, the sum of -1 and +1 equals zero.