Step 1: Understanding the Concept:
The Present Perfect Continuous tense is used for an action that started in the past and is still continuing in the present.
Step 2: Detailed Explanation:
The use of the word "since" followed by a specific point in time (2015) indicates the duration of an ongoing activity.
The structure for Present Perfect Continuous is: Subject + has/have + been + Verb+ing.
"She" is a singular subject, so we use "has been living".
Options (A), (B), and (C) do not account for the continuity from a specific past point to now in the presence of "since".
Step 3: Final Answer:
The correct form is "has been living". Therefore, option (D) is correct.