Answer:
q is an explanatory variable
Step-by-step explanation:
An explanatory variable is often considered as a predictor variable or an independent variable. More or less, the two variables or terms can be interchanged to mean ALMOST the same thing. THE ONLY DIFFERENCE IS THAT; AN INDEPENDENT VARIABLE is not affected by any other variables while this is not totally true for an explanatory variable(because it influence response variable).
Explanatory variables are often manipulated in experiments by the person doing the experiment, that is the researcher and explanatory variable is used in the prediction of differences in the response variable.