The answer is: C) Non-experimental cause to effect study. People need to stop leaving wrong answers. Here I am giving answers every time I finish my quiz only to have a bad grade because of people leaving purposeful wrong answers...

The answer is: All of the above.   a)  People can overlook alternative common threads or differences.  b) People can focus on the irrelevant differences or common threads.c) People can fail to consider the possibility of coincidence.  d) All of the above