The value of waiting

A trader can act now or wait one week for a "talks / no talks" signal, with likelihoods of "talks" equal to $(0.8,0.5,0.1)$ under (deal, stalemate, escalation) and prior $(0.5,0.3,0.2)$. The actions are flat, long one Nifty futures lot, or long futures plus a 23,000 put, with payoffs (₹) from Worked example 12.3:

If the trader waits, 20% of the deal-scenario rally is missed (deal payoffs on the futures leg fall by 20%), while other payoffs are unchanged. (a) Build the decision tree and solve it by backward induction. (b) What is the optimal policy? (c) Compute EVPI under the prior and compare it with the value of the one-week signal.