Answer :
Answer: Extemporaneous
Explanation: Extemporaneous is the way of giving or delivering speech with slight preparation or no preparation at all.The speaker tends to have skill of giving unrehearsed speech and does not require speech preparation.Speaker takes help of short notes,manuscript etc for speaking.
According to the mentioned situation in question, even though Sofia has prepared the speech but has not rehearsed it rather she is using note points to deliver the speech.This displays that she does not want to give practiced speech.
Thus, the delivery form used by Sofia is extemporaneous for delivering speech.