Answer:
The correct answer is option C, that is, the speed of a typical sneeze.
Step-by-step explanation:
There are three main kinds of variables found in a scientific experiment. These are the independent variable, dependent variable, and the controlled variable. The independent variable is the one that can be manipulated or monitored, the dependent variable is the one, which gets influenced by the changes made to the independent variables, and the control refers to the variable that must be held constant.
It is important to keep the control variable the same all through the test or the experiment. As any variation in a control variable would invalidate the association between the independent and the dependent variable, thus, hampering the outcomes. In the given experiment, it is known that the speed of a general sneeze is 100 miles per hour, thus, it cannot be changed and can be used as control while performing the given experiment.