Since the pronoun is supposed to represent "one of the boys" the answer is A. his. You want a singular pronoun so it wouldn't be C or D. B might fit but it does't make sense since we're assuming the boy was bringing his own camera.
I am working on the office
noun + verb + ing - present tense
Edward de Vere was the famous writer who wrote Shakespeare's plays on the side of philosophical and political career.
I think it means that she was growing older, or turning sixty years old, and had no time to waste doing what she's doing.
The correct answer in this case is "we"
Us is also correct but in that case the sentence would not be an elliptical one. If you use "we" then the sentence is both correct and elliptical which fits the description of the question.