The Chief Minister was given a warm welcome at the onset of the function.

The correct answer is: B. commencement.

The onset of a function is the beginning of the function. The Chief Minister was given a warm welcome at the beginning of the function, so the answer is commencement.

Hindrance is an obstacle or difficulty that prevents something from happening. Finale is the final part of something, especially a piece of music or a play. Conclusion is the end of something.