20 distinguishable basketball players participate in Winter League. They are being divided uniformly at random into 4 distinguishable teams, A, B, C, D, of 5 players each. The order of the players within the teams does not matter. Now, it turns out that 5 of the 20 players are actually WNBA players. (a) Calculate the probability that the 5 WNBA players end up on the same team. (b) What is the expected number of teams that have at least one WNBA player? Remember to describe the probability space and to justify your answers