Assumption Q

[supersuj]

If a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the air than there would be otherwise. Therefore if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced.

Which one of the following is an assumption on which the argument depends?

A) Cutting down on pollution can be achieved in a variety of ways.
B) Taking public transportation rather than driving is not always feasible.
C) Walking is the only feasible alternative to driving that results in a reduction in pollution.
D) There are people who never drive but who often walk.
E) People sometimes drive when it is feasible to walk instead.

PS: My answer does not match the OA. I just want to understand why i am wrong. Thanks. Source-LSAT

[RonPurewal]

If a person chooses to walk rather than drive, there is one less vehicle emitting pollution into the air than there would be otherwise. Therefore if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced.

Which one of the following is an assumption on which the argument depends?

A) Cutting down on pollution can be achieved in a variety of ways.
B) Taking public transportation rather than driving is not always feasible.
C) Walking is the only feasible alternative to driving that results in a reduction in pollution.
D) There are people who never drive but who often walk.
E) People sometimes drive when it is feasible to walk instead.

PS: My answer does not match the OA. I just want to understand why i am wrong. Thanks. Source-LSAT

answer here should be (e).

the best way to verify this - as is the case for other "find the assumption" problems - is to use the REVERSAL TEST:
negate the assumption, and see whether the argument is invalidated.

if you negate choice (e), you get "people already walk whenever it's feasible to walk." if that's the case, then the argument is destroyed, because there's no further shift possible from driving to walking.

[JbhB682]

Hi - I don't understand why C is incorrect unfortunately ...

Negating C, following is my negation

Walking is NOT the only alternative to driving in order to reduce pollution

In other words

There are other ways other than walking to reduce pollution

To me, this destroys the argument which is. ... (if you walk instead when you can drive, pollution is reduced)

To me, negating C does destroy the argument...

Please let me know, where am i going wrong

[Sage Pearce-Higgins]

Good use of the negation test. Be sure that you're clear what the argument is claiming. The conclusion isn't claiming that walking is the only way to reduce pollution. The conclusion is 'if people would walk whenever it is feasible for them to do so, then pollution will be greatly reduced'. Now if we take the negation of answer C, 'There are other ways other than walking to reduce pollution', the conclusion isn't destroyed; it might still be true. Sure, they may be other ways to reduce pollution, but that doesn't mean that walking makes no difference.