Fill in the blank (_) in the following sentence from the following choices.
Sentence: The board broke in half when shot by the arrow because the _ was weak.

Choice 1: The board broke in half when shot by the arrow because the board was weak.
Choice 2: The board broke in half when shot by the arrow because the arrow was weak.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
1. The board was weak.