Advertisement:Do you want to be more energetic, vigorous, ... ...

Which of the following would most strengthen the advertisement’s claim that Vita-Plus supplements make one more energetic and alert?
(A) Those who voluntarily chose to take more than 2 capsules daily reported energy levels even greater than those who took only 2 capsules.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Nova Press: Set J - More CR Practice