Cantantes. Which is singers but it’s the most related to your question.
The an should be A, the first choice.
There is no image so I don’t know
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 best place to start learning to speak in spanish is google translation text what you want to learn in it and then write it down and look over it till you memorize it or you can go online and learn spanish from websites .
<span>Espero que me ayudó!</span>