Answer:
D. grades at school
Step-by-step explanation:
The dependent variable is the thing in the research process whose value is changing in relation to another variable.
It depends on the independent variable, the one who is controlled by the scientist to see how the dependent variable changes.
Therefore, we can see that dependent variable changes in contrast to the independent one, and as the independent variable changes, scientists observe and record the changes of the dependent variable to conclude the results.
In this case, scientists change cultural influence or hours spent playing video games, or some other thing they chose as the independent variable. What will then change are grades are school - they will observe and record how grades in school change according to other parameters, and define results of academic performance through them. Therefore, grades are the dependent variable.