Determine the topic of the question-answer pair. Question: "what cars have smart key systems?"; Answer: "It was first developed by Siemens in the mid-1990s and introduced by Mercedes-Benz under the name "Keyless Go" in 1998 on the W220 S-Class following its design patent filed by Daimler-Benz on May 17, 1997."? Topic:
Ans: Smart key

Determine the topic of the question-answer pair. Question: "how does a solid state drive work?"; Answer: "A solid-state drive (SSD) (also known as a solid-state disk or electronic disk, though it contains no actual "disk" of any kind) is a data storage device using integrated circuit assemblies as memory to store data persistently ."? Topic:
Ans: Solid-state drive

Determine the topic of the question-answer pair. Question: "what is middle class in the us?"; Answer: "Depending on class model used, the middle class may constitute anywhere from 25% to 66% of households."? Topic:
Ans: American middle class

Determine the topic of the question-answer pair. Question: "what is tmz stand for?"; Answer: "The name TMZ stands for the historic " studio zone " or 30-mile zone radius from the intersection of West Beverly Boulevard and North La Cienega Boulevard in Los Angeles."? Topic:
Ans: TMZ (website)