Answer:
Option a is correct
Explanation:
Given that y varies directly as x
Hence y can be written as kx
y=kx where k is the constant of proportionality
To find k:
Use the fact that y=7 when x=3
We get
7 =3k
OR k =

Hence the relation between x and y is

To find y value when x=7:
From the relation we found we substitute x =7 to find y

Option a is correct