Given the task definition and input, reply with output. 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.

Passage: Former resident Sonia Freeman (Lynn Rainbow, who filmed all of her scenes in just one day) returns to Number 96 after her release from a mental asylum. Sonia is now married to newspaper journalist Duncan Hunter. Her forgetful episodes and hallucinations become increasingly erratic and deranged. This worries Duncan, Sonia's good friend Jack Sellars and Jack's new girlfriend, flight attendant Diana Moore, who has moved into flat 6. It is revealed that Diana and Duncan are secretly scheming to drive Sonia insane. Jack and the police arrive just in time before Diana and Duncan can persuade Sonia to kill herself.
Aldo has been withholding cash takings from the deli to avoid paying income tax on it, but loses the money in a fire. He takes a night job at the Connaught Rooms function hall to recoup the losses.
Many of the residents become embroiled in the major plans for Dorrie and husband Herb's (Ron Shand) Ruby Wedding celebrations. After looking at her marriage certificate, Dorrie discovers that the best man Horace Deerman signed where the groom should have. Believing this means Dorrie is married to Horace, Dorrie, Herb and Flo track him down. Horace is revealed as a derelict alcoholic. Much to her dismay, Horace takes a fancy to Dorrie.
Les enlists Herb and Alf to assist in his new business venture: a sauna in the building's basement, unbeknownst to wife Norma.
What is the last name of the person who is working with Duncan to drive someone crazy?