Source 1: The Loch Ness monster must exist. More than 10,000 people claim to have sighted the serpent-like monster. Can 10,000 people all just be imagining things? Sonar studies and expeditions have not been able to prove them wrong!

Source 2: With today's underwater cameras and sonar, it's impossible to believe that the Loch Ness monster exists. We would have found her by now! When scientists with the latest technology cannot find a trace of the monster, we have to conclude that it's all a myth.
Question
Read the passages. What do they have in common?
Responses
A. a topic

B. a main idea

C. an overall message

D. a purpose