Which of the following best describes effectiveness in communication?

Effectiveness in communication is best described as successfully achieving one's communicative goals. This concept underscores the primary purpose of communication, which is to convey a message or information in such a way that the intended outcome is realized. Whether it is persuading an audience, informing them of specific details, or encouraging discussion, the key measure of effectiveness lies in whether those objectives have been met.

The other choices, while they may contribute to effective communication, do not encompass its essence. Employing humor can enhance engagement but doesn't guarantee that the message is understood or the goal achieved. Adhering to cultural norms in speech is vital for relatability and appropriateness but does not directly measure the success of the communication effort. Similarly, enunciating words clearly is an important aspect of delivery, yet clarity alone does not ensure that the intended message was received and acted upon as desired. Effectiveness is ultimately about the successful transmission and reception of communication, making the understanding and achievement of communicative goals the central focus.