Which is the basic programming language that I should choose for my new app?
I am sorry but I didn't quite understand your query here.Are you developing your own app or the app developer is giving you options?
Choose HTML as base language. It will be favorable for you in the future because it can be incorporated to other many languages.
Choose c++ language. This is the most appropriate and robust programming language when it comes to building mobile apps for Android, and mainly for low-level programming, it's still the go-to language on platforms for mobile app developers.