The answer is the option C, which is:
C. √29
The explanation of this exercise is:
To solve this problem you must apply the proccedure shown below:
1- You have that:
W (-2,8,-3) and X(1,4,-1)
2- Therefore, you can calculate the magnitude as below:
|WX|=√[(1-(-2)]²+(4-8)²+[(-1-(-3)]²)
|WX|=√29