Please help me with only part (b).

Rachel Duncan is the CEO of Dyad Pharmaceuticals, and she faces a decision about her company's newest and most promising drug candidate: NZT-48. Clinical trials have been completed, and the team awaits an approval decision from the U.S. Food and Drug Administration (FDA) before it can be marketed. In the meantime, Ms. Duncan receives an offer from a global biotech company, International Genetics Incorporated (InGen) to license NZT-48 from Dyad. (Licensing here means that InGen provides capital to help the development and launch process of the new drug, but will share the profits with Dyad once the drug enters the market.) With InGen's offer, Ms. Duncan has a decision to make right now, before the FDA's decision. She can accept InGen's offer. If FDA approves the new drug, then Ms. Duncan estimates that her company's valuation will reach $4 billion; if FDA does not approve, with InGen's injected capital, Ms. Duncan estimates that her company would still value at $1.5 billion. If Ms. Duncan rejects InGen's offer and brings the new drug to market by her own company, should FDA approves the drug, then Dyad may reach the valuation of $6 billion (since it would not need to share the profits with InGen); however, if FDA rejects the drug, Dyad's valuation may tumble to $1 billion. a) Let p denote the probability for FDA to prove the new drug. Draw a decision tree to represent the situation that Ms. Duncan faces, and identify all the strategies. b) Ms. Duncan and her team estimate that p = 0.5. Suppose that Ms. Duncan is risk averse, with a risk tolerance of $0.4 billion. (b.1) Using the exponential utility function, calculate the risk premiums of all the strategies identified in Part (a). (b.2) What decisions should Ms. Duncan make? (Please explain your answer.) c) While the estimated FDA approval probability is 0.5, Ms. Duncan is not sure of it. Please conduct a sensitivity analysis on p. (More specifically, discuss how Ms. Duncan's decision would change when p ranges from 0 to 1.)