Wally wants to do a study on video game playing and dexterity in middle school females as a population. He goes to the local middle school in his town and studies the dexterity of the girls in the "gamers club." He obtains the results on a Tuesday at 10am. He obtains almost the same results the following Tuesday, also at 10am. His study is: A) Valid for middle school females but not a reliable study. B) Not valid for middle school females but is a reliable study. C) Not valid for middle school females, and not a reliable study. D) Valid for middle school females and also a reliable study. E) None of the above.