I'm taking a test and have to guess the right answer to the question after the article. Article: Where do dogs come from? Gray wolves are their ancestors. Scientists are pretty consistent about that. And researchers have suggested that dogs' origins can date back to Europe, the Near East, Siberia and South China. Central Asia is the newest and best candidate, according to a large study of dogs from around the world. Laura M. Shannon and Adam R. Boyko at Cornell University, and an international group of other scientists, studied not only purebred dogs, but also street or village dogs. Dr. Shannon analyzed three different kinds of DNA, Dr. Boyko said, the first time this has been done for such a large and diverse group of dogs from 38 countries. And that led them to Central Asia as the place of origin for dogs in much the same way that genetic studies have located the origin of modern humans in East Africa. The analysis, Dr. Boyko said, pointed to Central Asia, as the place where "all the dogs alive today" come from. The data did not allow precise dating of the origin, he said, but showed it occurred at least 15,000 years ago. Greger Larson of Oxford University, who is leading a large international effort to analyze ancient DNA from fossilized bones, said he was impressed by the study. "It's really great to see not just the number of street dogs, but also the geographic breadth and the number of remote locations where the dogs were sampled," he said in an email. He also praised the sampling of different kinds of DNA and the analytic methods. Dr. Larson, who was not involved with the study, said he thought the Central Asia finding required further testing. He said he suspected that the origins of modern dogs were "extremely messy" and that no amount of sampling of living populations will be definitive. He said a combination of studies of modern and ancient DNA is necessary. Question: Who wasn't engaged in the study of dogs' origins? Options: A: Laura M. Shannon B: Adam R. Boyko C: Shannon and Boyko D: Greger Larson
The answer to this question is:
D