Which of these statements is the best description of a variable?

A) A variable is something the researcher believes is irrelevant to the research outcome.
B) A variable is something that can have only one value.
C) A variable is something that can have more than one value or score.
D) A variable is a scientific statement of observation.

A variable is something that can have more than one value or score, this means that it can vary or change depending on different factors or conditions. This is essential in research because researchers often need to identify and measure variables to study their relationship to other variables or outcomes. Option A is incorrect because any variable can potentially impact the research findings. Option B is incorrect because a variable can have numerous values or scores. Option D is incorrect because a variable is not a scientific statement of observation, but it refers to a concept or characteristic that can be observed and measured in a scientific study.