Which is the best choice? You must try to run ( ) as you can on the limited food and water that you have

Question

You must try to run ( ) as you can on the limited food and water that you have.

a) as wide
b) as long
c) as far
d) as possible

I deem b.c.d are all right. Which is the best one?

Answer 1

I'm sure the person who wrote the test wants you to give "C". In this position, an adverb is needed.

It is possible to "run wide", in the context of, for example, football. It means "Run along the edge of the pitch". It doesn't make much sense when combined with "on limited food"

You can talk about "a long run" (adjective), or "run for a long time". You could say "run for as long as you can" to mean "for a long time". You could even omit the word "for". So (b) is possible, but unlikely. In a test situation, you would not be dropping the word "for".

(c) is most likely. It refers to distance. The word "far" can act as an adverb without "for" or another proposition.

(d) doesn't make sense. You can't "run possible" because "possible" isn't an adverb. Moreover "as possible as you can" doesn't have a clear meaning.