)which sentence below shows correct use of em dashes?

by the end-of-the-story, no one could believe it the main-character, was dead.
by – the end of the story no one could believe it, the main – character was dead.
by the end of the story, no-one could believe it the main, character – was dead.
by the end of the story – no one could believe it – the main character was dead.

It was extremely base of him to desert you in your time of need. ( change into exclamatory sentence)

You suspect that this article has left out some facts that might lead the reader to believe that someone else made the star-spangled banner. what is the best way to verify this? by consulting a variety of sources by disregarding the article entirely by writing a letter to the editor of the publication that printed the article by reading various historical accounts by verifying the opinions

When is the best time to evaluate options? a. during the first step of decision-making b. as you identify options c. after you've identified many options