Hi!! A 690 puts you within the range for both schools, but on the lower edge. If you thought you could boost your score any higher, I would suggest taking the GMAT again - especially because you have time before you are applying to school. Given your major, there may be an expectation that your quant score could be higher. If you decide not to take the GMAT again, you might consider writing an optional essay where you lay out your quant skills.
Also, keep in mind that the AdComs aren't just looking at your score. They will also consider your professional experiences, extra-curricular activities (especially those where you take on leadership roles) and your recommendations. All of those factors are also very important in the application process.
Best of luck,
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