3. (3 Points) Determine the amount of consumer surplus [CS] generated in each of the following situations: (show your work). a. Sienna is willing to pay up to $30 for a new T-shirt. He picks out one he likes with a price tag of exactly $18. b. Ali goes to a store hoping to find a used copy of a favorite vinyl record album for up to a maximum of $20. The store has one copy selling for $20, which he buys. c. After soccer practice, Cassidy is willing to pay $2.5 for a bottle of water. The 7-Eleven sells water for $2.75 per bottle, so she declines to purchase it