Cuando hablas con una persona que no conoces debes usar "usted".
The correct answer is not A. Im sorry to say this but the correct answer is B. por la puerta de embarque (which will by by the gate). If you use the A option there would be a grammatical mistake putting the word "por" before something that makes no sense. Im a native spanish speaker and a teacher so believe the better way to say is por la puerta de embarque
The correct answer is ustedes
I think that the answer is C not to sure
