Answer:
The correctly punctuated sentence is the following one: The game, which lasted twelve innings, ended with a Red Sox victory!
Explanation:
"Which lasted twelve innings" is a nonessential relative clause. The information provided by the clause is not necessary to limit the noun "the game". The listener probably knows which game the speaker is referring to. That is why the the clause is offset from the rest of the sentence with commas. If it was removed, the sentence would still make sense and its meaning would be left unchanged (see 1).
1) The game ended with a Red Sox victory!
