Given the task definition, example input & output, solve the new input case.
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
Example: Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
Output: Who believes Fagin's gang make wallets and handkerchiefs?.
This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

New input case for you: Passage: The Tower is of brick and was the entrance to the cour d'honneur of the 1560s rebuilding. Of four storeys, it has recessed staircase turrets to each side, creating what the architectural historian Mark Girouard described as an "extraordinarily slender and elegant" appearance. The courtyard was open on the tower side, its three facades containing seven classical doorways. Girouard notes Horace Walpole's observation of 1752, "perfect and very beautiful". Such an arrangement of a three-sided courtyard with a prominent gatehouse set some way in front became popular from Elizabethan times, similar examples being Rushton Hall and the original Lanhydrock.The Tower was Sackville-West's sanctum; her study was out of bounds to all but her dogs and a small number of guests by invitation. Her writing room is maintained largely as it was at the time of her death. Nigel Nicolson records his discovery in the Tower of his mother's manuscript describing her affair with Violet Trefusis. This went on to form the basis of his book Portrait of a Marriage. The clock, below the Tower parapet, was installed in 1949. A plaque is affixed to the arch of the Tower; the words were chosen by Harold Nicolson: "Here lived V. Sackville-West who made this garden". Nigel Nicolson always felt that the memorial failed to acknowledge his father's contribution. The Tower has a Grade I listing.
Output:
What is the last name of the person who had an affair with Violet?