Science

It depends on what kind of role you are expecting in the government 'Secret Agency'. The criteria is general and as per industrial standard for the post of analyst, inspector, operations, etc. However, for upper authority and (or) military intelligence in RAW, NSG, etc., they don't go for direct hiring. They don't even really the selection criteria and process. In general, they do pick up the serviceman (based on the past history of record) from the army and civil services and after their selection, they undergo training for various projects. Hence for qualifications, there is nothing as such (Science, Commerce and Arts) but you must have an exceptional track record in service. Secondly, for skills, you should be a quick decision maker.