Given:
Four equations in the options.
To find:
The equation which represents a proportional relationship.
Solution:
If y is proportional to x, then
where, k is the constant of proportionality.
In this case if x=0, then y=0. It means the graph of a proportional relationship passes through the origin.
From the given options, only option B, i.e., , is of the
, where,
.
So, the equation represents a proportional relationship.
Therefore, the correct option is B.