Which of the following is not a method to discover reasons for the thesis?

Which of the following is not a method to discover reasons for the thesis?
A.We can go back to the 5-step Decision Package to look for reasons.
B.We can use mind maps to find out reasons for a thesis.
C.We can reflect on how we come to the conclusion/thesis in the first place.
D.We can copy other people’s opinions.
正确答案：We can copy other people’s opinions.