Geography

Why do you want to do your graduation again if you have already done it? It would be a wise choice if you do MA in economics after completing BA in geography if you are interested in economics. If you are in 12th and interested in economics you can directly pursue BA in economics.

Please check for your eligibility to appear for the CUCET exam from the criteria mentioned at the link provided below. CUCET 2018 eligibility criteria as stated by all participating institutions for the academic session, 2018-19 is given at the link provided below:
https://www.shiksha.com/science/exams/cucet.

Where do you wish to apply?

Please refer to the link provided below where you can check for eligibility to pursue this course from Marathwada Mitra Mandal's College of Commerce (MMCC). You should be able to download college brochure which contains details regarding this course like eligibility criteria, admissions, etc.
Regards.
https://www.shiksha.com/mba/course/post-graduate-diploma-in-foreign-trade-marathwada-mitra-mandal-s-college-of-commerce-mmcc-deccan-pune-235171

You can go for BA or B.Sc in geography and if you had maths along with economics, you can also apply for BA or B.Sc in economics.

Yes, you can, the only subjects that would be compulsory are geography and English.

Sure, you can sit for both exams. As minimum graduation percentage eligibility for CAT is 50%.

Hi Ankita, Economics is not mandatory. Geography (Hons) can be done by students passing 10+2 preferably with Geography as one of the subjects in 10+2 if you are seeking admission for the honours course. The criteria vary from college to college.