Ms. Lembke is a partner for DTS, a CPA firm. She is the lead partner for the firm's largest client, The Grey Elephant. Ms. Zadina, who works in the same office as Ms. Lembke, has a sister who is the controller for The Grey Elephant. Because of potential independence issues, Ms. Zadina does no work for The Grey Elephant. Ms. Zadina is being considered for promotion to partner. What independence issues should Ms. Lembke consider before promoting Ms. Zadina? Be sure to state the specific ruling as part of your answer.