Fill in the blank (_) in the following sentence from the following choices.
Sentence: Looking at organisms under the microscope, Jennifer identified Jessica's specimen, as _ had extensive knowledge of microbiology.

Choice 1: Looking at organisms under the microscope, Jennifer identified Jessica's specimen, as Jennifer had extensive knowledge of microbiology.
Choice 2: Looking at organisms under the microscope, Jennifer identified Jessica's specimen, as Jessica had extensive knowledge of microbiology.
Which of the choices is correct? Respond with only "1" or "2" and no additional text.
1
2.