Answer: THIRD OPTION.
Step-by-step explanation:
For this exercise you need to use the formula for calculate the distance between two points. This is:

Given the following points:
and 
You can identify that:

Knowing these values, the next step is to substitute them into the equation for calculate the distance between two points and then evaluate.
Therefore, the distance between
and
is:

13 is prime because there is only 1 factor 1 and 13.
V=2 BECAUSE
7v2+1=29
7v2=28
v2=4
v=2