Which of these is a well-defined question about tigers?

A. Are tigers better then lions

B. What size animal do tigers prefer to hunt

C. Which kind of animal is the most deadly hunter

D. How should humans prevent tigers from going extinct

D. How should humans prevent tigers from going extinct?

Explanation:

Definitely, tigers are the endangered species and it is estimated that all forms of tigers will go extinct within a decade. Therefore, scientists (ecologists, biologists) are trying to protect tigers and their habitats for their long term survival. The D option is thus correct because it gives sufficient knowledge as well as raise a technical issue (question) which is needed to be addressed on priority.

The remaining options are either not correct or don't reflect true information. For example, not all tigers are better than lions. Likewise, the size of animals doesn't matter in hunting for tigers. And, kind of animal which is a deadly hunter is least related to sole characteristics of tigers.