Since, in this case, we have 4 options then you just need to substitute each number.
A. y = 5/x
B. y = 14/x
C. y = 9/x
D. y = 3.5x 
We know that x= 2 when y=7. So...
A. y = 5/x
 7=5/2
 7=2.5 
 This is false.
B. y = 14/x
 7= 14/2
 7=7
 This is right, So True.
C. y = 9/x
 7=9/2
 7=4.5
 False
D. y = 3.5x 7=3.5(2)
 7=7
 This one is also true.
In this case we look for definition.
he statement " y varies inversely as x means that when x increases, y decreases by the same factor. In other words, the expression xy is constant:
xy = k 
where k is the constant of variation.
We can also express the relationship between x and y as:
y = k/x 
where k is the constant of variation.