One group of scientists feel that global warming affects the frequency of hurricanes. Another group of scientists believe that global warming does not affect the frequency of hurricanes, but it makes the average hurricane stronger. Which of these is the most likely reason the two scientists gave conflicting opinions on the impact of global warming on hurricanes?

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.