A scientist is studying the effect of glaciers on climate and feels that the melting of ice caps has produced global climate change. A climatologist says that global warming is not a problem with far-reaching consequences. An oceanographer feels that it is possible to build a giant machine to combat the consequences of global warming.

Which of these is the most likely reason the three scientists have different opinions on the consequences of global warming?

A.) They do not have enough knowledge on the topic.
B.) They did not discuss the issue among themselves.
C.) They believe conflicting opinion strengthens science.
D.) They study different areas of science and have different scientific focuses.