Communication occurs when ________.

The correct answer highlights the fundamental process of communication, which involves the transmission of a message from one person to another, along with the receiver's ability to decode it effectively. Communication is a two-way process, where the sender conveys information, and the receiver interprets that information to understand the intended meaning.

This choice underscores the importance of both the sending and receiving aspects of communication. The sender's message must be conveyed clearly, but it is equally vital that the receiver is able to understand and interpret that message accurately. If the message is not decoded properly, effective communication has not occurred, regardless of how well it was transmitted.

The other options touch on aspects of communication but do not capture its essence. For instance, agreement on the message content is significant, but it is not a prerequisite for the act of communication itself. Non-verbal cues contribute richness to communication but are not required for the basic transfer of information. Lastly, the absence of preconceived notions may improve understanding but is not a necessary condition for communication to take place.