Consider the following sequential game with two players, A and B. Player A decides to contribute or not to contribute to a public good and Player B observes his decision. In the case player A has decided not to contribute, the game ends with profit of 1 for player A and 0 for player B. In the case player A decide to contribute, both players simultaneously decide how much to contribute, either 1 or 2. In this case each one receives a profit equal to the sum of the contributions times 0.75 minus his contribution.

a. Represent this game in extensive form

b. Represent this game in normal form