First things first, bro, no doubt qualifying CA is a big achievement; hatsoff for this achievement of yours.
Now coming to the point.

Remember following points when choosing subjects.

Accounts is not just accounting but it is composite of financial and costing accounting in Accounting I paper and audit, taxation and business finance in accounting II paper. Being CA it would be really easy for you to prepare this paper without taking much stress.
Mercantile law is also suitable option for you bcz you have already studied it. But remember m.law also include other laws i-e company law, competition and 3 more. From which 1 question is examined in every paper. As you have already studied it it will not get much of your time.

Further bus. Ad is very promising for you bcz almost 70-80% of its course is reminiscent to your modcule E business management.

Gender studies is also a good choice and very scoring in last 2 attempts... course is a bit indigestable at first bcz of being finance guy but one can get over with it.
Last, chose subject that is more general and overlap with other subject. Journalism may also b considered...

Hope that helps...

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