Which of the Following Statements Correctly Applies to the Reliability

Which of the following statements correctly applies to the reliability of this exam?

A) If nearly everyone misses a particular question, this will lower the exam's reliability.
B) The best way to assess the exam's reliability is to carefully judge how representative the questions are of the course content.
C) Ambiguously worded questions that evoke guessing have little or no effect on reliability.
D) Increasing the number of questions on the exam is likely to increase its reliability.