Under what condition must acceptance be communicated to the offeror?

The correct answer revolves around the principle that acceptance of an offer generally needs to be communicated to the offeror, unless the offeror has explicitly waived this requirement. This means that if the offeror has stated or implied that acceptance does not need to be communicated formally—such as in cases where the offeror indicates that silence or an act can indicate acceptance—then the offeree is not required to notify the offeror of their acceptance.

This concept is grounded in the idea that parties to a contract must operate under terms they are both aware of and have agreed to. Acceptance must be clear and unambiguous; if the offer is made with a condition that allows for waiver of communication, then the acceptance can take place without direct communication.

The other options fail to capture this principle: requiring acceptance to be in writing, implying acceptance through conduct, or necessitating a prior relationship do not align with the fundamental rule regarding the necessity of communication unless expressly waived by the offeror. In contract law, the clarity of terms set by the offeror is pivotal to understanding obligations related to acceptance.