I have Raspberry Pi which needs to read sensor data through Bluetooth and I2C. I want to know the Linux operating system which will be well suited for this application.
Most of the OS's available for the Pi would be able to meet your requirements. However, as it appears from your question that you are fairly new to the Pi I would suggest Raspbian which is based on Debian. You can download it from here. The main reason for this suggestion is that there are simply more tutorials and a bigger user base running Raspbian than the other OS's. This will make it easier to find code samples and get help when you run into problems. I would also suggest downloading the full (not lite) version as it includes the GUI making some tasks easier.