Concept:Intonation refers to the rise and fall of the voice while speaking, which is a change in pitch.Explanation:Intonation is the variation in pitch during speech. Pitch is how high or low your voice sounds. When you ask a question, your pitch rises at the end. When you make a statement, your pitch often falls. Intonation helps express feelings, emphasis, and grammatical meaning. Without it, speech would sound flat and monotonous. The other options – sound, organ, and air – do not describe this pattern of voice movement. Only pitch changes create the melody of speech.Answer:B. pitch