The correct answer is option C, that is, students, learn more from video games than classrooms.
The Hawthorne effect refers to a term signifying the capability of some of the individuals to work harder and perform much better when they are taking part in an experiment. The term is generally implied to indicate that people may modify their behavior because of the attention they are obtaining from researchers in spite of doing any changes in the independent variables.
In the given case, the student learns math more from video games as they are completely involved in it, illustrated by the phenomenon known as the Hawthorne effect.