Client confidentiality

What legal principle is being violated when the defendant's attorney accesses the plaintiff's confidential communications with their attorney without proper authorization?

In a civil case, a plaintiff is suing a construction company for alleged breach of contract. The plaintiff claims that the construction company failed to complete a building project on time and within the agreed budget, leading to financial losses. During the pre-trial phase, the defendant's attorney, in an attempt to gain an advantage, accesses the plaintiff's confidential communications with their attorney without proper authorization.

Choices:

A) The duty to the court

B) The principle of fairness and equity

C) The attorney-client privilege

D) The duty of impartiality