A pizza vendor wants to know if customers prefer recipe A or recipe B to make the sauce. To do this, he randomly selects 3 of his frequent customers and, without telling them which pizza has what sauce, he gives them to try a pizza with A and another with B. The order in which he gives the pizzas to each customer is random, and the customers don't know what the difference is between the pizzas. Each customer is asked which pizza he liked the most and he points to A or B according to the customer's response. Assuming that in reality in the total population there is no preference for either of the two recipes, a) Show in table form what is the sampling distribution of the estimated proportion? b) Is it an unbiased estimator? Prove your answer.