The object of the Sentence Completion section of the SAT is for the test-taker to complete the given sentence using context clues.
A sentence completion question may have one or more blanks, and five answers to choose from. For example:
Scotland is a nation in the north of the Island of Great Britain; it has a(n) _________ economy that distinguishes it from the rest of the United Kingdom.
- A. dignified
- B. self-sufficient
- C. fancy
- D. unique
- E. complex
We can use context to help us select the correct answer. The blank is clearly describing Scotland's economy. From the rest of the sentence, we can determine that we know two things about Scotland - it's in the north of Great Britain and its economy distinguishes it somehow. So, the blank must relate to one of those things. The geographic location of Scotland is probably irrelevant when describing its economy, so the blank must mean something relating to 'distinguishing'.
While distinguished can sometimes relate to being (A) dignified, that is not how the word is being used in this context, and while (B), (C), and (E) may be true, only (D) unique means the same thing as being distinguished, i.e. standing out.
Therefore, the answer is D. unique.