Answer:
The fourth sentence
Step-by-step explanation:
The fourth sentence uses the dash appropriately, utilizing it to introduce an appositive structure.
The first three sentences, however, fail to use them correctly.
- Instead of a dash, a stop would have been more appropriate to separate both sentences. Alternatively, dropping the expletive and the verb, leaving just the Noun Phrase would work just fine.
- While separating various words of the same category, in this case nouns, commas get the job done.
- Time periods such as 18th century or The Middle Ages do not utilize dashes in between. Neither does the verb mined with the adverb today.