CDS

Both the Air Force Common Admission Test and the combined defense services are conducted to select suitable candidates for training in the academies for the post of commissioned officer in the Indian Armed Forces. While the complete AFCAT procedure is conducted by the Air Force and the CDS exam is conducted by UPSC The SSB for both exams is conducted by respective SSB boards. Selected students go through the SSB interview, and those who are recommended by the Services Selection Board undergo a medical examination. Only students declared medically fit are issued joining letters, subject to their rank in the final merit list calculated on the basis of the aggregate mark in written and SSB interviews.

B.A will be a better option if you want to make your career by clearing CDS exam. But for INA and Air force Academy you must have a degree in Engineering.
For INA: The aspirants must have a degree in Engineering. For Air Force Academy: The aspirants should have passed 12th standard with Physics and Mathematics and having a degree from a recognised university or Bachelors degree in engineering / technology. As we Know Why all prefer B.A. For CDS preparation because there are three different exams are organised by UPSC.
EXAM-I Elementary mathematics
EXAM-II English
EXAM-III General studies
So, if you go for B.A. for your graduation, you will have an advantage of preparing for third exam in parallel with your graduation. But you should choose subjects wisely as per exam syllabus because if your sociology and all this will not be beneficial as per your target. Believe me GK of CDS is quite tough. Questions are also asked about world. Most importantly, you have to gain at least 20% in each exam so that your OMR sheets go for checking. H

No, there is no strong data available that all short-service officers (OTA) do corporate jobs after serving for 10 years in the army. This is for multiple reasons:
1. Some officers prefer to extend their service tenure for four more years, as per army rules.
2. Around 5 percent get a permanent commission, depending on the vacancy.
3. Some other officers prefer to go for other government jobs, such as railways, as there are relaxations and quotas for ex-servicemen in many government jobs.
4. Some prefer to do higher studies, such as an MBA or Ph.D. before starting a new career.
5. Some other SSC officers choose to guide defense aspirants to achieve their goals. Therefore, not all SSC officers choose to take this path to start a new career after retirement.

The General Knowledge (GS) paper of CDS is a bit tricky due to the vast syllabus. This strategy may help you sail through the GS paper of CDS:
1. Since the syllabus is vast therefore you need to analyze the previous year's papers to understand the pattern of repeating topics.
2. You must select the most frequently occurring themes and properly prepare them. For other topics, you may simply have an idea about the topic.
3. You do need to study or solve each and every question as there is a negative marking. Simply mark those questions about which you are sure.
4. Read current affairs-related subjects well, such as polity and security, as it will help you in SSB also.
5. Similarly, a strong foundation in Science and geography is also necessary to score well in the GS paper. You can be a little selective in the history section.
6. Do not ignore current events and allow adequate time to revise this section.
7. Practice as much as possible to improve your accuracy in the GS Paper. Best Wishes.