Let's first break down the passage. We are told that people who are never asked to do more than they can easily do are people who never do all they can. This is an S->N statement that we can abbreviate and write as: NOT A (not asked) -> NOT DAC (not do all they can). We are then told that Alex has not done all he can, which means he meets our Necessary condition of NOT DAC. From this, the passage assumes that this means Alex was never asked to do more than what comes easily to him, or NOT A, which is our Sufficient condition. This is where the flaw occurs- the passage uses the existence of the Necessary condition to assume the existence of the Sufficient condition, which is backwards.
(A) is correct because it makes the same mistake as the passage- using the Necessary condition to assume the Sufficient condition. We are given the S->N statement: D -> C. We are then told that Alicia has C, and mistakenly assume that this means she must also have D.
(D) is incorrect because it exhibits valid reasoning, whereas the passage exhibits flawed reasoning. (D) is unique because it introduces a definition, so we can think of this as an "if and only if" statement. In other words, the statement can be thought of as both: (1) If you're a polygon -> then you're a closed plane figure bounded by straight lines, and (2) If you're a closed plane figure bounded by straight lines -> then you're a polygon. Therefore, the passage's flaw of using the Necessary condition to assume the Sufficient condition would not be a flaw here because each variable is both Sufficient and Necessary.
Does that make sense? Please let us know if you have any other questions!
jingjingxiao11111@gmail.comApril 14, 2020
Thanks. Definition is an IF AND ONLY IF statement really threw me off on this one! Your answer saved my day!
