Lets take a look at the line. We see that the point is between 5 and 6, which means A is wrong. Now lets just count the number of lines between the two points, where 5 is starting at 5 0/6 and 6 is 5 6/6. So as we go, we find that the point B is 4/6 of the way to 6. This means that the best answer is B) 5 4/6.
I hope this helps! :)