From the given equations as the possible answer options, y = 9x is the correct answer which represents a proportional situation.
Two values (variables in this case) are said to be proportional if they change in a way such that there is a constant multiple multiplied to one of the values.
Here, in the equation y = 9x, y and x are the two variable and 9 is the constant multiple.
If two quantities are said to have a proportional relationship if they vary in such a way that one of the quantities is a constant multiple of the other i.e,
y = |k|x ; where |k| is constant proportionality.
By definition :
y =9x where k =9 is constant , represents a proportional relationship.
