Question: The Orion Nebula, is a diffuse nebula situated in the Milky Way, being south of Orion's Belt, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion, and consists of how many bright stars?
Context: The Horsehead Nebula (also known as Barnard 33) is a dark nebula in the constellation Orion.  The nebula is located just to the south of the star Alnitak, which is farthest east on Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex.  The nebula was first recorded in 1888 by Scottish astronomer Williamina Fleming on photographic plate B2312 taken at the Harvard College Observatory.  The Horsehead Nebula is approximately 1500 light years from Earth.  It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which bears some resemblance to a horse's head when viewed from Earth. Barnard's Loop (catalogue designation Sh 2-276) is an emission nebula in the constellation of Orion.  It is part of the Orion Molecular Cloud Complex which also contains the dark Horsehead and bright Orion nebulae.  The loop takes the form of a large arc centered approximately on the Orion Nebula.  The stars within the Orion Nebula are believed to be responsible for ionizing the loop. The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion.  It is one of the brightest nebulae, and is visible to the naked eye in the night sky.  M42 is located at a distance of 1,344 ± 20 light years and is the closest region of massive star formation to Earth.  The M42 nebula is estimated to be 24 light years across.  It has a mass of about 2000 times the mass of the Sun.  Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula. Sh2-279 (alternatively designated S279 or Sharpless 279) is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion.  It is the northernmost part of the asterism known as Orion's Sword, lying 0.6° north of the Orion Nebula.  The reflection nebula embedded in Orion's Belt or the Belt of Orion, also known as the Three Kings or Three Sisters, is an asterism in the constellation Orion.  It consists of the three bright stars Alnitak, Alnilam and Mintaka. The Orion correlation theory (or Giza–Orion correlation theory) is a hypothesis in alternative Egyptology.  Its central claim is that there is a correlation between the location of the three largest pyramids of the Giza pyramid complex and Orion's Belt of the constellation Orion, and that this correlation was intended as such by the builders of the pyramids.  The stars of Orion were associated with Osiris, the god of rebirth and afterlife, by the ancient Egyptians. Depending on the version of the theory, additional pyramids can be included to complete the picture of the Orion constellation, and the Nile river can be included to match with the Milky Way galaxy.  The theory was first published in 1989 in "Discussions in Egyptology", volume 13.  It was the subject of a bestseller, "The Orion Mystery", in 1994, as well as a BBC documentary, "The Great Pyramid: Gateway to the Stars" (February 1994), and appears in some new-age books. The Orion Molecular Cloud Complex (or, simply, the Orion Complex) is a large group of bright nebulae, dark clouds, and young stars in the Orion constellation.  The cloud is between 1 500 and 1 600 light-years away, and hundreds of light-years across.  Several parts of the nebula can be observed through binoculars and small telescopes, and some parts (such as the Orion Nebula) are visible to the naked eye. Messier 43 (also known as M43, De Mairan's Nebula, and NGC 1982) is an H II region in the Orion constellation.  It was discovered by Jean-Jacques Dortous de Mairan before 1731.  The De Mairan's Nebula is part of the Orion Nebula, separated from the main nebula by a lane of dust.  It is part of the much larger Orion Molecular Cloud Complex. Orion's Sword is an astronomical asterism in the constellation Orion.  It comprises three stars (42 Orionis, Theta Orionis, and Iota Orionis) and M42, the Orion Nebula, which together are thought to resemble a sword or a scabbard.  This group is situated under the prominent asterism, Orion's Belt, where it points in a southerly direction.  Origins behind Orion's Sword are based in mostly greco-roman tradition, though this group of stars is referenced as a weapon in multiple cultural contexts (see below). V380 Ori is a young multiple star system located near the Orion Nebula in the constellation Orion, thought to be somewhere between 1 and 3 million years old.  One of the component stars appears to have launched a polar jet that helped to clear the keyhole-shaped hole in the surrounding nebula known as NGC 1999.  The system is surrounded by a bow shock—the total structure over 17 light-years (5.3 parsecs) across.  V380 Orionis is a quadruple star system.  The two main stars (until now known collectively as V380 Orionis Aa) are a spectroscopic binary system, the stars orbiting each other over a period of 106 days.  The primary is a hot white Herbig Ae/Be star of spectral type B9 that has a surface temperature of 10,500 ± 500 K, and is around 2.87 times as massive and 100 times as luminous as the Sun, and is triple its diameter.  The secondary is a T Tauri star that has a surface temperature of 5,500 ± 500 K, and is around 1.6 times as massive and 0.31 times as luminous as the Sun, and is twice its diameter.  The two stars are surrounded by a circumstellar disk, lying almost edge-on to observers on earth.
Answer: three