which of the following is the best statement regarding the relationship between different forms of validity in psychology research? a. it is difficult to achieve high levels of both internal and external validity in the same research study. b. if one has high external validity in a research study, then they automatically have high internal validity as well. c. there is no relationship between internal and external validity, as they examine different qualities of a study. d. it is not possible to simultaneously assess both internal and external validity, so a researcher must decide which one is more important to their study before the research begins.