Final answer:
The correct answer to fix the punctuation in the given sentence is option D.
Step-by-step explanation:
The correct sentence that fixes the punctuation in the given sentence is option D: I am really looking forward to visiting the Dalmatian Coast, located along the western coast of Croatia, since my family was planning on touring the area via a sailboat. This sentence correctly places commas to separate the appositive phrases 'located along the western coast' and 'of Croatia'. It also uses a comma before the conjunction 'since' to separate the two clauses.
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