Hello honey
Before the experts answer - I will tell you one thing from what I do know.
All 3 German manufacturers you mention produce cars that are termed as premium just by brand itself. Very few can afford anything made by Mercedes, BMW and Audi in India.
Manufacturing is a must because import duties are prohibitive. Also now you are no longer allowed to import left hand drive cars (the kind you normally drive)
The most common car brands you will see on Indian streets are Japanese, Korean and Indian brands. Not German.
Also, the most appreciated (earlier Czech, now) German cars are made by Skoda (probably due to the luxury vs the price), which you have not mentioned.