A cover letter is an accompanying letter that serves as
the introduction to your resume. No resume should be
sent without one. The cover letter is individualized for
each position for which you are applying. It is an
extension of your resume and reflects your knowledge
of the employer’s needs.
The correct answer for the question that is presented is this one: "The Greeks inside the horse remain quiet because if they create noise, their plan won't be easily be done. The reason why they stay inside the horse because they want to secretly go inside the place and start to attack.