input question: What is the question to: "The North American Free Trade Agreement (NAFTA) is an agreement signed by Canada , Mexico , and the United States , creating a trilateral trade bloc in North America ."? The topic is North American Free Trade Agreement.???
output answer: "What is the purpose of North American Free Trade Agreement?"


What is the question to: "Located at the mouth of the Yodo River on Osaka Bay , Osaka is Japan's third largest city by population after Tokyo (special wards) and Yokohama ."? The topic is Osaka.
----
Answer: "where is osaka japan?"


Q: What is the question to: "A mathematical constant is a special number , usually a real number , that is "significantly interesting in some way"."? The topic is Mathematical constant.
A: "what is a constant in math??"


Question: What is the question to: "Wendy Williams Hunter (born Wendy Joan Williams; July 18, 1964) is an American media personality , actress and author."? The topic is Wendy Williams.
Answer: "what nationality is wendy williams?"


[Q]: What is the question to: "The at sign @ is also commonly called the at symbol, ampersat, apetail or commercial at in English—and less commonly a wide range of other terms."? The topic is At sign.
****
[A]: "what is the @ sign called??"


Problem: Given the question: What is the question to: "In the maintenance of file systems , defragmentation is a process that reduces the amount of fragmentation ."? The topic is Defragmentation.
++++++++++++++++++++++++++++++++
The answer is:

"What is the disk defragmenter tool?"