Answer:
Option C is the correct option.
Explanation:
The given expression is 

Further we simplify the expression as 

Now if we put the value of x as 1, 2, 3, 4
Then 

For x = 1
y = 1/7×1 = 1/7
For x = 2

For x = 3 

That means when we increase the value of x value of y gets increased.
Therefore y varies directly as 

Option C is the correct option.