Pleas explain part b. I understand part a.

1. (35) Consider a variation of the Glosten-Milgrom sequential trade model where the asset's value V can take three values. Suppose that the true value of stock in Trident Corporation can be, with equal probability, either VH = , VI = , or some middle value VM. Let a = of the traders be informed insiders, while the remaining 1 a = are uninformed noise traders. Assume as always that informed traders always buy when V = VH and sell when V = VL, while uninformed traders buy or sell with equal probability. The focus of this problem is the traders' behavior when V = VM. (a) (5) Draw the tree diagram, leaving uncertain the action of informed traders when V = VM. (b) (5) Show that there is no value of VM for which informed traders randomize between buying and selling