Answer and Explanation:
In case when there is an existence of the mutual relationship lies between the two variables so it can be said it is a correlation. In case when one variable rises, and the other is also rises so it is positive and in the case when one variable rises, and the other is fall so it is negative
Now the classification is as follows
a. Spent more time that results in more marks so positive correlation
b. In case when the vaccination rises, the illness decreased so negative correlation
c. No relation lies between the soft drink and the music paid so no correlation
d. Increase in education results more income so positive correlation