Passage: Upon his return to his family home, Angel has two letters waiting for him: Tess's angry note and a few cryptic lines from "two well-wishers" (Izz and Marian), warning him to protect his wife from "an enemy in the shape of a friend". He sets out to find Tess and eventually locates Joan, now well-dressed and living in a pleasant cottage. After responding evasively to his enquiries, she tells him Tess has gone to live in Sandbourne, a fashionable seaside resort. There, he finds Tess living in an expensive boarding house under the name "Mrs. d'Urberville." When he asks for her, she appears in startlingly elegant attire and stands aloof. He tenderly asks her forgiveness, but Tess, in anguish, tells him he has come too late. Thinking he would never return, she has yielded at last to Alec d'Urberville's persuasion and has become his mistress. She gently asks Angel to leave and never come back. He departs, and Tess returns to her bedroom, where she falls to her knees and begins a lamentation. She blames Alec for causing her to lose Angel's love a second time, accusing Alec of having lied when he said that Angel would never return to her.

Question: What is Tess' assumed name?
Mrs. d'Urberville