The general common application (not a section specific to a school) asks for a career interest. How much weight does the choice hold? If I cannot decide between two fields, say scientific researcher and physician, is putting one or the other a better option?
If you cannot decide, then evaluate your classes, ECs and any community service. Which of the two jobs is better supported by the ~4 years of you efforts / which job does your unique personal narrative better support?
IMO this question really isn’t too important as most people don’t know what they want to do til well after high school.
The question holds no weight at Princeton. If you were applying to Olin College and put that you wanted to be a Lawyer then they might question your application.
My son marked “undecided” and was accepted.