Critical Reasoning

Source: Veritas Prep [800score]

A new study reports that every U.S. president has had an IQ that placed him in the top two percent of the population: 138 or above. However, a different study focusing on leadership ability and potential concluded that the optimal IQ for a national leader is 125-above average, but not in the top two percent. Therefore, no United States president has had an IQ optimal for a national leader.

Which of the following, if true, most seriously weakens the conclusion above?

A. John F. Kennedy's IQ as reported in the second study was 127; in the first, 159.
B. A president's election in the US depends less on his leadership potential than on the public's perception of his intelligence.
C. Leadership ability in the second study was determined by studying the IQs of current national leaders from 100 different countries around the world.
D. The calculation of IQ is not an exact science; the margin of error can be as great as 3-4%.
E. IQ is only one of many factors that determines a national leader's success.

OA: A

I think A is the only feasible option.

It proves that the study and its conclusions are itself flawed giving skewed results on the same sample : hence the conclusion is weakened.

what's the OA?

Whats the Source ? Veritas ?

I got it.

"A" explains that both the studies provided different IQ that matches with above one.

what is the correct answer

OA is A

Why Not C.
I thought A seems to be saying that the Leaders were judged on different Parameters in the 2 studies.
In the First 1 :Intelligene
2nd :leadership Potential
Its very well possible that a person gets judged on Different Parameters and gets Different Gradings in 2 Different Studies
Guys who choase A , i think, went with what seems to be the most common technique of undermining the credibilty of the study to weaken the Conclusion.