Binomial distribution is a widely employed discrete probability distribution in statistics where a set of independent observations constitutes exactly two disjoint outcomes of a trial. Therefore in binomial distribution, an outcome of a random experiment can be classified under two different categories. For example, when a die is tossed once we observe six different numbers, that is x = 1, 2, 3, 4, 5 and 6. If we classified these outcomes as even or odd numbers then we will get two different outcomes. Likewise we can separate the turnover of a company into two categories, such as above and below the target level. Also, we can separate the exam grades simply into two categories, satisfactory and poor. The correct answer is A.