The required equation is: 
Option C is correct.
Step-by-step explanation:
The proportional relationship can be found using the equation: 
where x and y are the points and k is the constant of proportionality.
We need to find k.
From the graph given, we can locate points x and y:
x=5, y= 35 then k would be:

x=10, y=70 then k would be:

For each values of x and y, the constant of proportionality k is 7
So, the required equation is: 
Option C is correct.
Keywords: Proportional Relationship
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