Context and question: Fox announced on May 11, 2015 that the fifteenth season would be the final season of American Idol; as such, the season is expected to have an additional focus on the program's alumni. Ryan Seacrest returns as host, with Harry Connick Jr., Keith Urban, and Jennifer Lopez all returning for their respective third, fourth, and fifth seasons as judges.
How many seasons of American Idol have there been?
Answer: 15
Context and question: METRO began light rail service on January 1, 2004, with the inaugural track ("Red Line") running about 8 miles (13 km) from the University of Houston–Downtown (UHD), which traverses through the Texas Medical Center and terminates at NRG Park. METRO is currently in the design phase of a 10-year expansion plan that will add five more lines. and expand the current Red Line. Amtrak, the national passenger rail system, provides service three times a week to Houston via the Sunset Limited (Los Angeles–New Orleans), which stops at a train station on the north side of the downtown area. The station saw 14,891 boardings and alightings in fiscal year 2008. In 2012, there was a 25 percent increase in ridership to 20,327 passengers embarking from the Houston Amtrak station.
 When did Texas start using light rail lines?
Answer: unanswerable
Context and question: The structure of QD-LEDs used for the electrical-excitation scheme is similar to basic design of OLEDs. A layer of quantum dots is sandwiched between layers of electron-transporting and hole-transporting materials. An applied electric field causes electrons and holes to move into the quantum dot layer and recombine forming an exciton that excites a QD. This scheme is commonly studied for quantum dot display. The tunability of emission wavelengths and narrow bandwidth is also beneficial as excitation sources for fluorescence imaging. Fluorescence near-field scanning optical microscopy (NSOM) utilizing an integrated QD-LED has been demonstrated.
 A Quantum Dot non-LED has been used in what?
Answer:
unanswerable