The unit rate of the proportional relationship y= 2x is

We have that the unit rate is 2 [Option B].
***Explanation***
We have that a proportional relationship is characterized for having the form:
[tex]a=kb[/tex]Here a and b are the values that are proportional to one another and k is the constant of proportionality.
In our case we are given:
[tex]y=2x[/tex]Here x & y are the proportional values and 2 is the constant of proportionality.
And, from properties of division, we have that:
[tex]\frac{2}{1}=2[/tex]