The correct answer is: Shy voters, educational levels, and the observer effect led the public to believe Clinton would win the election.
During the 2016 election cycle, factors such as the so-called "shy voter" phenomenon, where some voters were reluctant to express their support for Trump due to social stigma, alongside differences in educational levels affecting perceptions of candidate support, contributed to the public and polls indicating a stronger likelihood of a Clinton victory. The observer effect also played a role in shaping public expectations and opinions based on perceived outcomes of polling data.