Final answer:
The correct punctuated line of dialogue is "Don't get mad at me!" Milo said, raising his hands. "I'm just the messenger." because it properly uses punctuation and capitalization within and after the quoted speech.
Step-by-step explanation:
The punctuated line of dialogue that is correct is: "Don't get mad at me!" Milo said, raising his hands. "I'm just the messenger." This sentence correctly places the exclamation mark within the quotation marks, uses a comma after the closing quotation mark, and before the attribution (Milo said), and starts the next piece of dialogue with a capital letter. The other options contain punctuation and capitalization errors, such as missing commas after dialogue tags, incorrect placement of periods, or lack of capital letters at the beginning of a new sentence within dialogue.