Finish the game.

The correct answer is: A. The game had to be finished.

The other options are incorrect because they do not express the same level of necessity as the first option. The second option, “Let the game be finished,” suggests that the game is optional, while the third option, “The game should be finished,” suggests that the game is desirable but not essential. The fourth option, “Let the game finish,” is grammatically incorrect.

The first option, “The game had to be finished,” expresses the strongest sense of necessity. It suggests that the game is not only desirable but also essential. This option is the most accurate interpretation of the original sentence.