In Germany you have deliberately opened a letter that is addressed to another person. What have you not respected?

EDITORIAL LEARNING AID

Why is this answer correct?

Letters are protected by the confidentiality of correspondence (Article 10 of the Basic Law); you may not open other people's mail, and doing so can be a criminal offence. Answer b is therefore correct. The right to remain silent (a) concerns statements in proceedings, the duty of confidentiality (c) concerns professional secrets, and freedom of expression (d) has nothing to do with other people's mail.

Opening other people's letters violates the confidentiality of correspondence (Art. 10).

This translation and explanation are editorial learning aids. The official German wording and answer key govern the examination.