There should be 1 independent variable in an experiment.
An experiment can be defined as a scientific procedure that is carried on to support a hypothesis. The experiments are usually performed in a laboratory but sometimes they can be carried out elsewhere.
Some experiments can be based upon human elements that are carried on to study the market, or demand for a product or a service. They are generally carried by a company. Therefore the experiment is dynamic.
The experiments involve 1 independent variable that is not influenced by any other factor. The effects of change in this independent variable are observed in other variables that are dependent on the independent variable.
Therefore the correct option is b.
Learn more about an experiment here:
https://brainly.com/question/9199868
