Step 1: Analyzing the options.
The sentence needs to describe the mistake that people commonly make.
- (D) introduces the subject: "many people have made is," which sets up the structure.
- (A) explains the specific mistake: "thinking that it."
- (B) explains the effect: "would be a waste of time."
- (C) concludes by indicating the action people fail to do: "to work together."
Step 2: Conclusion.
The correct order is: "One common mistake that many people have made is thinking that it would be a waste of time to work together."
Thus, the correct answer is 1. (D), (A), (B), (C).
Final Answer:
\[
\boxed{\text{The correct answer is 1. (D), (A), (B), (C).}}
\]