What is the extent to which an experiment has effectively controlled for confounding variables?
a. external validity
b. case study
c. internal validity
d. confounding variable

C) Internal Validity

Explanation:

Internal validity in terms of confounding variable is defined as the control mechanism which monitors an experiment so that confounding does not occur.As confounding mechanism can result in more than one cause to occur at the same ti me of research or experiment.Thus , confounding is controlled to decrease it and increasing the internal validity

Other option are incorrect because external validity permits occurrence of external variable in research and experiment.Case study is the content research in form of case.Confounding variable produce numerous cause at a particular time. Thus, the correct option is option(C).

probably 3 since archeologists and historians don’t understand there writing.