Fill in the blank (_) in the following sentence from the following choices.
Sentence: Mark had to cut down the oak tree in his yard because the _ was too big.

Choice 1: Mark had to cut down the oak tree in his yard because the oak tree was too big.
Choice 2: Mark had to cut down the oak tree in his yard because the yard was too big.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
1.