Concept:Intonation changes the meaning of a statement.
Falling tone on a statement: the speaker is sure; it is a plain statement of fact (certainty).
Rising tone on a statement: it becomes a question, showing doubt, surprise or disbelief ("He is here? I did not expect that.").
Explanation:"He is here." said with a rising tone sounds like "Is he here?", so the speaker is not sure:
doubt.
Certainty is shown by the falling tone, not the rising tone.
Emphasis is shown by stress on a word, and determination by a firm falling tone, not a rise.
Key point: The stored key gave C (certainty), which is the meaning of the falling tone; a rising tone on a statement expresses doubt.
Answer:Option D (Doubt)