Answer:
C). weight hung from the spring
Step-by-step explanation:
An Independent variable is characterized as the variable that is controlled or manipulated by the experimenter in order to observe its change on the dependent variable.
In the given experiment, 'weight hung from the spring' is the independent variable as it is manipulated by the researcher in order to witness its impact on the dependent variable(how the spring stretches). It is the cause that causes an effect on the dependent variable. Any change in the former directly affects the latter. Thus, option C is the correct answer.