The correct answer is: The Chairman will inaugurate the annual function.
The Chairman is the person who will be opening the annual function. This is a formal event, and it is important that the person who opens it is someone who is respected and has a high position in the company or organization. The Chairman is the most appropriate person to open the annual function because they are the head of the company or organization.
The other options are not correct because they do not accurately reflect the information in the question. Option B, “The Chairman may inaugurate the annual function,” is not correct because it does not state that the Chairman will definitely inaugurate the function. Option C, “The Chairman inaugurated the annual function,” is not correct because it does not state that the Chairman will inaugurate the function in the future. Option D, “The Chairman has inaugurated the annual function,” is not correct because it does not state that the Chairman will inaugurate the function in the future.
In conclusion, the correct answer is: The Chairman will inaugurate the annual function.