Answer:
B) end user
Step-by-step explanation:
End-user is the type of the customer or simply the user who ends up using the product. They don't have to personally buy the product in order to use it.
In this particular case, Sabrina's toy was gifted to her by someone else o her seventh birthday. She didn't make the decision for this specific toy, and she is not the customer herself. Sabrina is just playing with it - using it - which marks the ending status of the buying process.