Answer:
C. attach.
Explanation:
<em>In the passage, the words "...or attach..." come right after the word "secure" to further help the reader understand the intended meaning of "secure".</em>
Here is just an example:
How gracious of you to accept my apology, after losing the bag that contained the present.
Answer: B.
Explanation: Option D is discarded because the sentence clearly needs to have its punctuation fixed; option C is wrong because the independent clause "it was unbelievable..." cannot be introduced with a comma, and while options A and B seem viable, the abrupt interruption of the normal flow of the sentence demands the use of dashes.
