A
It bases a projection only on conservative estimates rather than considering a wider range of estimates.
B
It takes for granted that the options it considers are mutually exclusive.
C
It fails to consider the possibility that the rate of increase in traffic will start to diminish after ten years.
D
It fails to address the issue of the cost of traffic gridlock to the city’s economy.
E
It presents a choice that is limited to two options, without giving reasons for not considering any other options.
Muriel: I admire Favilla’s novels, but she does not deserve to be considered a great writer. The point is that, no matter how distinctive her style may be, her subject matter is simply not varied enough.
John: I think you are wrong to use that criterion. A great writer does not need any diversity in subject matter; however, a great writer must at least have the ability to explore a particular theme deeply.
Summary
Muriel believes that Favilla is not a great writer, because her subject matter isn’t varied enough.
John states that having varied subject matter is not required to be a great writer. Rather, a great writer must have the ability to explore a theme deeply.
Very Strongly Supported Conclusions
Favilla might be a great writer, even if her subject matter isn’t varied.
A
Even if the subject matter in Favilla’s writings is not particularly varied, she should not thereby be excluded from being considered a great writer.
Strongly supported, because John states that varied subject matter is not a requirement for being a great writer. So one can be a great writer even if one’s subject matter is not varied.
B
Even if Favilla cannot explore any particular theme deeply in her writings, she should not thereby be excluded from being considered a great writer.
This is anti-supported, because John states that ability to explore themes deeply is a requirement for being a great writer.
C
If Favilla has explored some particular theme exceptionally deeply in her writings, she deserves to be considered a great writer.
John doesn’t state what is sufficient to consider someone a great writer. He describes one necessary condition for being a great writer, but this doesn’t support a claim that someone deserves to be considered a great writer.
D
If the subject matter in Favilla’s writings were exceptionally varied, she would not deserve to be considered a great writer.
John does not state that having exceptionally varied subject matter prevents one from being a great writer.
E
If Favilla’s writings show no evidence of a distinctive style, she does not deserve to be considered a great writer.
John does not state that having a distinctive style is a requirement for being considered a great writer.
Essayist: Every contract negotiator has been lied to by someone or other, and whoever lies to anyone is practicing deception. But, of course, anyone who has been lied to has also lied to someone or other.
Summary
The stimulus can be diagrammed as follows:
Notable Valid Inferences
Every contract negotiator has lied to someone, and therefore practiced deception. If a person has not practiced deception, they are not a contract negotiator.
A
Every contract negotiator has practiced deception.
This must be true. As shown below, by chaining the conditional claims, we see that all contract negotiators must have lied to someone and, in extension, have practiced deception.
B
Not everyone who practices deception is lying to someone.
This could be false. Practicing deception is not a sufficient condition for anything in our stimulus, which means there are no implications from knowing someone practices deception.
C
Not everyone who lies to someone is practicing deception.
This must be false. Whoever lies to anyone is practicing deception.
D
Whoever lies to a contract negotiator has been lied to by a contract negotiator.
This could be false. No information in the stimulus suggests that if someone lies to a contract negotiator they have been lied to by one in the past.
E
Whoever lies to anyone is lied to by someone.
This could be false. We know that anyone who has been lied to has lied to someone, but we don’t know if this conditional relationship goes both ways, as (E) suggests.