Q8 - It is widely believed

[WaltGrace1983]

A recent study showed no difference between 80 year olds' and 30 year olds' abilities in playing a card game designed to test perception and memory

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Perception and memory doesn't significantly reduce from age 30 to 80

The flaw here could be a few. It could be that, just because the card game is designed to test perception and memory does not mean that it actually adequately fulfills its task. It could be that the card game requires hardly any perception and memory so that it wouldn't show any noticeable differences between a 30 y.o. and an 80 y.o. Maybe this card game isn't representative? I am going to go into the answer choices with these thoughts in mind looking for a flaw that matches

(A) We don't care about other cognitive abilities other than perception and memory

(B) This might actually strengthen the argument, albeit only slightly. Remember, we are looking for something to talk about a relative ability between 30 and 80 year olds and this answer choice is more about absolute ability

(C) This doesn't point to any flaw in the argument. Even if we are or aren't aware, so what? That is not what the argument is about. We don't need them to be/not be interrelated and this has no bearing on the argument

(D) It doesn't matter where these beliefs stem from. All that matters is that we find the flaw regarding how a card game does not definitely prove the conclusion that 30 and 80 year olds do not have drastically different abilities in memory and perception.

(E) This is a flaw that I pre-phrased. If the cards game requires very little perception and memory (noticed how this is exactly what the argument is talking about) then perhaps it is impossible to really make such a conclusion given the premise.

[roflcoptersoisoi]

There was no discernible difference in the abilities of 80 year olds and 30 year olds to play a card game, designed to test perception and memory.

The belief that perception and memory are reduced by age 80 is false.

Flaw(s): Takes for granted that the test actually tests perception and memory.
Fails to consider that those with reduced perception and memory can easily play the game.

(A) Descriptively accurate due to the limited scope of the stimulus, but it doesn't describe the flaw, eliminate
(B) If anything, the author seems to take this for granted and thus doesn't fail to consider this. Eliminate.
(C) Same as A
(D) Same as a and C
(E) Bingo. This matches nicely with the second flaw I identified.