help please,

{Darwiche 5.6) (10 pts) Lisa is given a fair coin C1 and asked to ip it eight times in a row. Lisa also has a biased com CZ, with a probability 0.8 of landing heads. All we know is that Lisa ipped the fair coin initially, but we believe that she intends to switch to the biased coin, and that she tends to be 10% successful in performing the switch. Suppose that we observe the outcome of the eight coin ips and want to nd out whether Lisa managed to perform a coin switch and when. (a) Describe a Bayesian network and a corresponding query that solves this problem. (b) What is the solution to this problem assuming the ips came out as follows: i. tails, tails, tails, heads, heads, heads, heads, heads. ii. tails, tails, heads, heads, heads, heads, heads, heads