Detailed Instructions: 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.
Q: Passage: Oan, angered by the BBC's incorrect reporting of his demands the previous evening, contacted the police negotiators shortly after 06:00 and accused the authorities of deceiving him. He demanded to speak with an Arab ambassador, but the negotiator on duty claimed that talks were still being arranged by the Foreign Office. Recognising the delaying tactic, Oan told the negotiator that the British hostages would be the last to be released because of the British authorities' deceit. He added that a hostage would be killed unless Tony Crabb was brought back to the embassy. Crabb did not arrive at the embassy until 15:30, nearly ten hours after Oan demanded his presence, to the frustration of both Oan and Sim Harris. Oan then relayed another statement to Crabb via Mustapha Karkouti, a journalist also being held hostage in the embassy. The police guaranteed that the statement would be broadcast on the BBC's next news bulletin, in exchange for the release of two hostages. The hostages decided amongst themselves that the two to be released would be Hiyech Kanji and Ali-Guil Ghanzafar; the former as she was pregnant and the latter for no other reason than his loud snoring, which kept the other hostages awake at night and irritated the terrorists.Later in the evening, at approximately 23:00, an SAS team reconnoitred the roof of the embassy. They discovered a skylight, and succeeded in unlocking it for potential use as an access point, should they later be required to storm the building. They also attached ropes to the chimneys to allow soldiers to abseil down the building and gain access through the windows if necessary.
A:
Who attached ropes to the chimneys to allow soldiers to abseil down the building?