In a bertand oligopoly, Two street vendors sell the same pair of sunglasses right across the street from each other. When they arrive first thing in the morning, they each put up a sign with their prices for the day at the same time. Each pair of sunglasses costs all of them $2. Customers are willing to pay $5 for a pair of these sunglasses. Suppose the two vendors show up every morning for many days, and each day there is a chance that the local government will pass an ordinance banning street ending. What is the highest value of for which the vendors can coordinate on a price of $5 using Grim Trigger strategies? (a) 1/3 (b) 1/2 (c) 2/3 (d) 3/4