M: It is almost impossible to find a person between the ages of 85 and 90 who primarily uses the left hand.
Q: Seventy to ninety years ago, however, children were punished for using their left hands to eat or to write and were forced to use their right hands.
Q’s response serves to counter any use by M of the evidence about 85 to 90 year olds in support of which one of the following hypotheses?
(A) Being born right-handed confers a survival advantage.
(B) Societal attitudes toward handedness differ at different times.
(C) Forcing a person to switch from a preferred hand is harmless.
(D) Handedness is a product of both genetic predisposition and social pressures.
(E) Physical habits learned in school often persist in old age.
NB: Good for mental muscles but I don't think GMAT contains this type of questions.
Maybe this is an Inference type question
(A) Being born right-handed confers a survival advantage. (Good choice, M states that only right handed people survived till 90 years and all the left handed people did not. This has been countered by Q by stating that a lot of left handed children were forced to use their right hand. We cannot be sure as there could be left handed people above the age of 90)
(B) Societal attitudes toward handedness differ at different times. (Maybe, but there is no mention of the present attitudes, eliminate)
(C) Forcing a person to switch from a preferred hand is harmless. (Not relevant)
(D) Handedness is a product of both genetic predisposition and social pressures. (Good Choice, M has stated something which looks like it has got to do something with the genes, but Q has countered it by stating that it was due to social pressures)
(E) Physical habits learned in school often persist in old age. (Not relevant)
Why is A correct and D wrong?
For D, No where it is mentioned in Q that the childer are able to do it, they are punished, forced but its not that they use it properly.
Since in M- old age people use Right hand, in Q- they were forced to user Right hand. So it implies that being born right-handed is advantageous.So A seems better choice.