TASK DEFINITION: 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.
PROBLEM: London's defences were rapidly reorganised by General Pile, the Commander-in-Chief of Anti-Aircraft Command. The difference this made to the effectiveness of air defences is questionable. The British were still one-third below the establishment of heavy anti-aircraft artillery AAA (or ack-ack) in May 1941, with only 2,631 weapons available. Dowding had to rely on night fighters. From 1940 to 1941, the most successful night-fighter was the Boulton Paul Defiant; its four squadrons shot down more enemy aircraft than any other type. AA defences improved by better use of radar and searchlights. Over several months, the 20,000 shells spent per raider shot down in September 1940, was reduced to 4,087 in January 1941 and to 2,963 shells in February 1941.

SOLUTION: Who reorganised London's defences?

PROBLEM: UNFPA is the world's largest multilateral source of funding for population and reproductive health programs. The Fund works with governments and non-governmental organizations in over 150 countries with the support of the international community, supporting programs that help women, men and young people:

SOLUTION: UNFPA is the largest worldwide funder of what type of programs?

PROBLEM: Ann Arbor's "Tree Town" nickname stems from the dense forestation of its parks and residential areas. The city contains more than 50,000 trees along its streets and an equal number in parks. In recent years, the emerald ash borer has destroyed many of the city's approximately 10,500 ash trees. The city contains 157 municipal parks ranging from small neighborhood green spots to large recreation areas. Several large city parks and a university park border sections of the Huron River. Fuller Recreation Area, near the University Hospital complex, contains sports fields, pedestrian and bike paths, and swimming pools. The Nichols Arboretum, owned by the University of Michigan, is a 123-acre (50 ha) arboretum that contains hundreds of plant and tree species. It is on the city's east side, near the university's Central Campus. Located across the Huron River just beyond the university's North Campus is the university's Matthaei Botanical Gardens, which contains 300 acres of gardens and a large tropical conservatory.

SOLUTION:
What is the city of Ann arbor nicknamed as?