This is known as the "Longest Answer Strategy." When more time is put into developing a response, chances are it is correct.

In a multiple choice question, incorrect answers should be distractions. These distractions should be selected by people who are unsure of the answer & ignored by those who do.

Sophisticated quiz-takers see clues to deduce correct answers: differences in grammar, length, formatting, and language choice.

More Info: cft.vanderbilt.edu