The correct answer is option 3: Parliament. The Public Accounts Committee (PAC) is a committee that is constituted by the Parliament in many countries, including India and the United Kingdom. The PAC is a crucial oversight body that is responsible for examining and scrutinizing the government`s financial accountability and transparency.

Option 1: President - The President, in most parliamentary systems, is the head of state and does not typically have a direct role in the constitution of specific committees like the Public Accounts Committee.

Option 2: Prime Minister - The Prime Minister is the head of government and is responsible for the day-to-day administration of the country. While the Prime Minister may have some influence over the formation of committees, the specific constitution of the Public Accounts Committee is typically the prerogative of the Parliament.

Option 4: Public - While the Public obviously has an interest in the workings and accountability of the government, they do not directly constitute the Public Accounts Committee. The public`s involvement is mainly through the elected representatives in Parliament who form and oversee the functioning of such committees.

In summary, the Public Accounts Committee is constituted by the Parliament and not by the President, Prime Minister, or the general public.