Phuc is playing a math quiz containing 20 questions. The probability of Phuc getting a question correct is 90%. This probability is the same for every question. Each question relates to a different area so the questions are considered independent. Let the random variable be the number of questions Phuc answers incorrectly. What is the appropriate probability distribution of this variable? Select one: a. Poisson distribution. O b. Normal distribution. O c. None of the answers listed. O d. Binomial distribution