To figure this out you just have to know what it means and it means:
Carolina: Where did you buy the tickets?
Sandra: Right here. In that ________ in front
Now that we know what the sentence means we will use the process of elimination to find the right answer. This is what every single word means:
A. Armchair
B. Box office
C. Gallery
D. Chicken coop
To use process of elimination we just cross out the wrong answers. We automatically know that C and D are wrong because they make no sense when put in the sentence. And we know that B will have to be correct since it is the only word that will fit into the sentence.