Who is responsible for marshalling the first passengers into the terminal building when there are 180 passengers and 4 infants onboard?

The responsibility for marshalling passengers into the terminal building typically falls to ground staff. Ground staff are specifically trained to manage the flow of passengers during boarding and deboarding processes. They ensure that the movement of passengers is organized and efficient, especially in scenarios where there are a large number of passengers, such as 180, along with additional needs for families traveling with infants.

Flight crew and cabin crew primarily focus on in-flight safety, comfort, and service rather than managing the terminal operations. Security personnel's role is more centered around safety and security checks rather than directing passengers to the terminal. Therefore, the ground staff play a crucial role in this context, making them the correct answer for marshalling the passengers.