Final answer:
Rehabilitation is necessary for a client who has had a stroke with left-sided hemiparesis to prevent further complications and improve function.
Step-by-step explanation:
The nurse would respond to the client by choosing option C) "To prevent further complications and improve function." Rehabilitation is necessary for a client who has had a stroke with left-sided hemiparesis because it helps prevent further complications and improves the client's ability to function. Through physical, occupational, and speech therapy, the client can relearn and regain lost functions, allowing them to achieve a better quality of life.