Exercise 9.15 Consider the following decision network:

a) What are the initial factors. (You do not have to give the tables; just give what variables they depend on.)

(b) Show what factors are created when optimizing the decision function and computing the expected value, for one of the legal elimination orderings.
At each step explain which variable is being eliminated, whether it is being summed out or maximized, what factors are being combined, and what factors are created (give the variables they depend on, not the tables).

(c) If the value of information of A at decision D is zero, what does an optimal policy look like? (Please give the most specific statement you can make about any optimal policy.)