A/an is a type of variable that is not accounted for in a research experiment.

The Answer is C, The independent and the dependent variable are the x and y axis and the only one left is the confounding variable.

Confounding variables are not accounted during the experiment.

During experiment out of the lot of variables, some variables are considered as constant or errors (in the sense of statistics). The confounding variables can be defined as variables that have the effects on both dependent and independent variables but cannot take in the experiment due to some restrictions. for example, if we are observing the effect of temperature on plant height, then the temperature will be the independent variable and plant height will be dependent. But we do not consider the rain or water in the experiment which also has the effect on plant height. So, rain will be confounding variable.