Because Heuristics Is Subjective, How Does a Researcher Know Whether

Because heuristics is subjective, how does a researcher know whether the findings are valid?

A) The findings aren't valid because validity only applies to objective or quantitative studies.
B) The findings are valid because only the researcher knows what is valid in the context of his or her essential experiences.
C) Validity itself is a subjective concept that post-empirical science has called into question.
D) The findings are valid if they comprehensively and accurately portray the meanings of the experience being studied.