Answer:
4th number line.
Explanation:
The other 3 number lines don't make sense.
#1: The dot is between 10 and 15, and -18 is less than 15, so incorrect.
#3: The dot is between -15 and -10, and -18 is lesser, so incorrect.
#2: The dot is between 10 and 15, and -18 is negative, so incorrect.
∴ #4 number line is correct