This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Occupancy sensors to allow operation for whenever someone is within the area being scanned can control lighting. When motion can no longer be detected, the lights shut off. Passive infrared sensors react to changes in heat, such as the pattern created by a moving person. The control must have an unobstructed view of the building area being scanned. Doors, partitions, stairways, etc. will block motion detection and reduce its effectiveness. The best applications for passive infrared occupancy sensors are open spaces with a clear view of the area being scanned. Ultrasonic sensors transmit sound above the range of human hearing and monitor the time it takes for the sound waves to return. A break in the pattern caused by any motion in the area triggers the control. Ultrasonic sensors can see around obstructions and are best for areas with cabinets and shelving, restrooms, and open areas requiring 360-degree coverage. Some occupancy sensors utilize both passive infrared and ultrasonic technology, but are usually more expensive. They can be used to control one lamp, one fixture or many fixtures.
What sensor controls light with motion sensors?

The city remained in the hands of Christian troops until 1102, when the Almoravids retook the city and restored the Muslim religion. Although the self-styled 'Emperor of All Spain', Alfonso VI of Leon and Castile, drove them from the city, he was not strong enough to hold it. The Christians set it afire before abandoning it, and the Almoravid Masdali took possession on 5 May 1109. The event was commemorated in a poem by Ibn Khafaja in which he thanked Yusuf ibn Tashfin for the city's liberation.The declining power of the Almoravids coincided with the rise of a new dynasty in North Africa, the Almohads, who seized control of the peninsula from the year 1145, although their entry into Valencia was deterred by Ibn Mardanis, King of Valencia and Murcia until 1171, at which time the city finally fell to the North Africans. The two Muslim dynasties would rule Valencia for more than a century.
In what year did Christian troops lose control of Valencia?

Great Britain: The torch relay leg held in London, the host city of the 2012 Summer Olympics, on April 6 began at Wembley Stadium, passed through the City of London, and eventually ended at O2 Arena in the eastern part of the city. The 48 km (30 mi) leg took a total of seven and a half hours to complete, and attracted protests by pro-Tibetan independence and pro-Human Rights supporters, prompting changes to the planned route and an unscheduled move onto a bus, which was then briefly halted by protestors. Home Secretary Jacqui Smith has officially complained to Beijing Organising Committee about the conduct of the tracksuit-clad Chinese security guards. The Chinese officials, seen manhandling protesters, were described by both the London Mayor Ken Livingstone and Lord Coe, chairman of the London Olympic Committee as "thugs". A Metropolitan police briefing paper revealed that security for the torch relay cost 750,000 and the participation of the Chinese security team had been agreed in advance, despite the Mayor stating, "We did not know beforehand these thugs were from the security services. Had I known so, we would have said no."
Which city hosted the 2012 Summer Olympics?