We need to remember that when two variables are in an inverse relationship, we have that, for example:

In this case, we have an inverse relationship, and we have that when x = 1, y = 12.
Therefore, we have that the correct relationship is:

In this relationship, if we have that x = 1, then, we have that y = 12:

Therefore, the correct option is the second option: y = 12/x.