Final answer:
The correctly punctuated sentence is 'D) Sparky, you are one sweet puppy!'. It includes a necessary comma for direct address and an exclamation point for emphasis without overuse of punctuation.
Step-by-step explanation:
The correct punctuation for the given sentence is D) Sparky, you are one sweet puppy! This sentence requires a comma after the name 'Sparky' since it is used as a direct address to the puppy. The exclamation mark at the end expresses strong emotion or enthusiasm about the subject, and there is no need for additional commas between 'one' and 'sweet' or after 'puppy' as they are not separating independent clauses or elements in a series.