Answer:
Yvonne
Step-by-step explanation:
In grammar, the doer of the action in a sentence is the subject, while the receiver of the action is the object.
There are direct object and indirect object and the difference is the direct object is found in a simple sentence and is the one that receives the action in that sentence.
Therefore, based on the simple sentence,
"I threw the ball to Yvonne.*, the direct object is Yvonne because she is the receiver of the ball