Which of the Following Statements About Scientific Research Studies Is

Which of the following statements about scientific research studies is the most accurate?

A) If the hypothesis is confirmed, the study is considered valid.
B) If the hypothesis is not confirmed, the study is considered invalid.
C) No study can be considered valid unless it is replicated.
D) It is impossible to control for every variable, so if one looks hard enough, a flaw can be found in almost any study.