In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

The top is held in place with?, Context: Inner and outer vestibules lead to the octagonal chapter house, which is of exceptional architectural purity. It is built in a Geometrical Gothic style with an octagonal crypt below. A pier of eight shafts carries the vaulted ceiling. To the sides are blind arcading, remains of 14th-century paintings and numerous stone benches above which are innovatory large 4-light quatre-foiled windows. These are virtually contemporary with the Sainte-Chapelle, Paris.
eight shafts

Where do Northwestern play?, Context: Northwestern fields 19 intercollegiate athletic teams (8 men's and 11 women's) in addition to numerous club sports. The women's lacrosse team won five consecutive NCAA national championships between 2005 and 2009, went undefeated in 2005 and 2009, added more NCAA championships in 2011 and 2012, giving them 7 NCAA championships in 8 years, and holds several scoring records. The men's basketball team is recognized by the Helms Athletic Foundation as the 1931 National Champion. In the 2010–11 school year, the Wildcats had one national championship, 12 teams in postseason play, 20 All-Americans, two CoSIDA Academic All-American selections, 8 CoSIDA Academic All0District selections, 1 conference Coach of the Year and Player of the Year, 53 All-Conference and a record 201 Academic All-Big Ten athletes. Overall, 12 of Northwestern's 19 varsity programs had NCAA or bowl postseason appearances.
NCAA

What type of electricity does Kenya primarily use?, Context: The largest share of Kenya's electricity supply comes from hydroelectric stations at dams along the upper Tana River, as well as the Turkwel Gorge Dam in the west. A petroleum-fired plant on the coast, geothermal facilities at Olkaria (near Nairobi), and electricity imported from Uganda make up the rest of the supply. Kenya's installed capacity stood at 1,142 megawatts between 2001 and 2003. The state-owned Kenya Electricity Generating Company (KenGen), established in 1997 under the name of Kenya Power Company, handles the generation of electricity, while Kenya Power handles the electricity transmission and distribution system in the country. Shortfalls of electricity occur periodically, when drought reduces water flow. To become energy sufficient, Kenya aims to build a nuclear power plant by 2017.

hydroelectric