Option 1 suggests that Zero Hour occurs before Question Hour, but this is incorrect. Zero Hour is actually a separate concept in the functioning of the Indian Parliament. Option 2 suggests that Zero Hour is the first hour of the session, but this is also incorrect. Zero Hour is not limited to just the first hour.

Zero Hour refers to the interval between the Question Hour and the next agenda. During this time, members of Parliament can raise important matters of public interest that require urgent attention. This is an opportunity for MPs to draw attention to pressing issues, make statements, or seek clarifications from ministers. It allows for discussions on urgent matters that may not have been listed on the agenda for the session.

Therefore, option 3 accurately defines Zero Hour in the working of the Indian Parliament.